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+I n t e r n a t i o n a l   T e l e c o m m u n i c a t i o n   U n i o n
+
+**ITU-T**
+
+TELECOMMUNICATION  
+STANDARDIZATION SECTOR  
+OF ITU
+
+**H.621**
+
+(08/2008)
+
+SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMS
+
+Broadband and triple-play multimedia services –  
+Advanced multimedia services and applications
+
+# --- **Architecture of a system for multimedia information access triggered by tag-based identification**
+
+Recommendation ITU-T H.621
+
+## ITU-T H-SERIES RECOMMENDATIONS AUDIOVISUAL AND MULTIMEDIA SYSTEMS
+
+|                                                                               |                    |
+|-------------------------------------------------------------------------------|--------------------|
+| CHARACTERISTICS OF VISUAL TELEPHONE SYSTEMS                                   | H.100–H.199        |
+| INFRASTRUCTURE OF AUDIOVISUAL SERVICES                                        |                    |
+| General                                                                       | H.200–H.219        |
+| Transmission multiplexing and synchronization                                 | H.220–H.229        |
+| Systems aspects                                                               | H.230–H.239        |
+| Communication procedures                                                      | H.240–H.259        |
+| Coding of moving video                                                        | H.260–H.279        |
+| Related systems aspects                                                       | H.280–H.299        |
+| Systems and terminal equipment for audiovisual services                       | H.300–H.349        |
+| Directory services architecture for audiovisual and multimedia services       | H.350–H.359        |
+| Quality of service architecture for audiovisual and multimedia services       | H.360–H.369        |
+| Supplementary services for multimedia                                         | H.450–H.499        |
+| MOBILITY AND COLLABORATION PROCEDURES                                         |                    |
+| Overview of Mobility and Collaboration, definitions, protocols and procedures | H.500–H.509        |
+| Mobility for H-Series multimedia systems and services                         | H.510–H.519        |
+| Mobile multimedia collaboration applications and services                     | H.520–H.529        |
+| Security for mobile multimedia systems and services                           | H.530–H.539        |
+| Security for mobile multimedia collaboration applications and services        | H.540–H.549        |
+| Mobility interworking procedures                                              | H.550–H.559        |
+| Mobile multimedia collaboration inter-working procedures                      | H.560–H.569        |
+| BROADBAND AND TRIPLE-PLAY MULTIMEDIA SERVICES                                 |                    |
+| Broadband multimedia services over VDSL                                       | H.610–H.619        |
+| <b>Advanced multimedia services and applications</b>                          | <b>H.620–H.629</b> |
+| IPTV MULTIMEDIA SERVICES AND APPLICATIONS FOR IPTV                            |                    |
+| General aspects                                                               | H.700–H.719        |
+| IPTV terminal devices                                                         | H.720–H.729        |
+
+*For further details, please refer to the list of ITU-T Recommendations.*
+
+# **Recommendation ITU-T H.621**
+
+# **Architecture of a system for multimedia information access triggered by tag-based identification**
+
+## **Summary**
+
+Recommendation ITU-T H.621 defines the system architecture for the multimedia information access triggered by tag-based identification on the basis of Recommendation ITU-T F.771, and serves as a technical introduction to subsequent definition of detailed system components and protocols. The services treated by this Recommendation provide the users with a new method to refer to the multimedia content without typing its address on a keyboard or inputting the name of objects about which relevant information is to be retrieved. This is one of the major communication services using identification (ID) tags such as radio frequency identifications (RFIDs), smart cards and barcodes. International standardization of these services will give a big impact to international multimedia information services using ID tags. It contains the functional model, its constituent components as well as its workflow. An appendix describes how this architecture realizes typical services.
+
+## **Source**
+
+Recommendation ITU-T H.621 was approved on 6 August 2008 by ITU-T Study Group 16 (2005-2008) under Recommendation ITU-T A.8 procedure.
+
+## **Keywords**
+
+Multimedia information access, tag-based identification.
+
+## FOREWORD
+
+The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis.
+
+The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics.
+
+The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1.
+
+In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC.
+
+## NOTE
+
+In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency.
+
+Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party.
+
+## INTELLECTUAL PROPERTY RIGHTS
+
+ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process.
+
+As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at <http://www.itu.int/ITU-T/ipr/>.
+
+© ITU 2009
+
+All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU.
+
+## CONTENTS
+
+|   |                                                                                                                  | <b>Page</b> |
+|---|------------------------------------------------------------------------------------------------------------------|-------------|
+| 1 | Scope .....                                                                                                      | 1           |
+| 2 | References.....                                                                                                  | 1           |
+| 3 | Definitions .....                                                                                                | 1           |
+|   | 3.1 Terms defined elsewhere.....                                                                                 | 1           |
+| 4 | Abbreviations and acronyms .....                                                                                 | 1           |
+| 5 | Conventions .....                                                                                                | 2           |
+| 6 | System functional architecture .....                                                                             | 3           |
+|   | 6.1 Functional components.....                                                                                   | 3           |
+|   | 6.2 Protocols.....                                                                                               | 5           |
+|   | 6.3 General workflow .....                                                                                       | 5           |
+|   | Appendix I – Examples of physical level architecture .....                                                       | 7           |
+|   | I.1 Configuration example of physical level architecture.....                                                    | 7           |
+|   | I.2 Components.....                                                                                              | 7           |
+|   | I.3 Implementation examples of narrow area communication between ID tag<br>and ID terminal.....                  | 8           |
+|   | I.4 Distributed implementation of ID resolution server.....                                                      | 10          |
+|   | Appendix II – Workflow examples for multimedia information access triggered by tag-<br>based identification..... | 12          |
+|   | II.1 Location-aware multimedia information service.....                                                          | 12          |
+|   | II.2 Multimedia information download via posters service .....                                                   | 13          |
+|   | II.3 u-Museum.....                                                                                               | 14          |
+|   | II.4 Business card with personal identifier.....                                                                 | 15          |
+|   | II.5 Presence service with multimedia information .....                                                          | 16          |
+|   | Bibliography.....                                                                                                | 18          |
+
+# **Introduction**
+
+This Recommendation defines the system architecture for multimedia information access triggered by tag-based identification and serves as a technical introduction to subsequent specifications of detailed system components and protocols. It contains the functional model, its constituent components as well as its workflow. An appendix describes how this architecture realizes typical services.
+
+## Recommendation ITU-T H.621
+
+# Architecture of a system for multimedia information access triggered by tag-based identification
+
+# 1 Scope
+
+This Recommendation defines the following issues to cover multimedia information access services triggered by tag-based identification as defined in [ITU-T F.771]:
+
+- a functional architecture reference model with descriptions of corresponding elements;
+- interface protocols between communication elements; and
+- a generic work flow to support multimedia information access triggered by tag-based identification.
+
+Moreover, this Recommendation describes implementation examples with work flows.
+
+# 2 References
+
+The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation.
+
+[ITU-T F.771] Recommendation ITU-T F.771 (2008), *Service description and requirements for multimedia information access triggered by tag-based identification*.
+
+<http://www.itu.int/rec/T-REC-F.771>
+
+# 3 Definitions
+
+## 3.1 Terms defined elsewhere
+
+This Recommendation uses the following terms defined elsewhere:
+
+- 3.1.1 **ID resolution:** [ITU-T F.771].
+- 3.1.2 **ID tag:** [ITU-T F.771].
+- 3.1.3 **ID terminal:** [ITU-T F.771].
+- 3.1.4 **identifier:** [ITU-T F.771].
+- 3.1.5 **multimedia information:** [ITU-T F.771].
+- 3.1.6 **multimedia information delivery function:** [ITU-T F.771].
+- 3.1.7 **real-world entity:** [ITU-T F.771].
+- 3.1.8 **tag-based identification:** [ITU-T F.771].
+
+# 4 Abbreviations and acronyms
+
+This Recommendation uses the following abbreviations and acronyms:
+
+- 2D            Two Dimensional
+- 3D            Three Dimensional
+
+|       |                                           |
+|-------|-------------------------------------------|
+| 3G    | Third Generation wireless systems         |
+| CD    | Compact Disk                              |
+| DNS   | Domain Name Server                        |
+| DVD   | Digital Versatile Disk                    |
+| GW    | GateWay                                   |
+| HTTP  | HyperText Transfer Protocol               |
+| ID    | Identification                            |
+| IDR   | Identification Resolver                   |
+| IDT   | Identification Terminal                   |
+| IP    | Internet Protocol                         |
+| IR    | Infrared                                  |
+| IRS   | Identification Resolution Server          |
+| MIDF  | Multimedia Information Discovery Function |
+| MIDS  | Multimedia Information Delivery Server    |
+| MIHF  | Multimedia Information Handling Function  |
+| MIM   | Multimedia Information Manager            |
+| MMS   | Multimedia Messaging Service              |
+| NFC   | Near Field Communication                  |
+| NGN   | Next Generation Network                   |
+| P2P   | Peer to Peer                              |
+| PDA   | Personal Digital Assistant                |
+| RF    | Radio Frequency                           |
+| RFID  | Radio Frequency Identification            |
+| R/W   | Reader/Writer                             |
+| SB    | Service Broker                            |
+| SIM   | Subscriber Identity Module                |
+| SMS   | Short Message Service                     |
+| URL   | Uniform Resource Locator                  |
+| WAP   | Wireless Application Protocol             |
+| Wi-Fi | Wireless Fidelity                         |
+
+# 5 Conventions
+
+In this Recommendation:
+
+- The expression "**is required to**" indicates a requirement which must be strictly followed and from which no deviation is permitted if conformance to this Recommendation is to be claimed.
+
+- The expression "**is recommended**" indicates a requirement which is recommended but which is not absolutely required. Thus this requirement need not be present to claim conformance.
+- The expression "**can optionally**" indicates an optional requirement which is permissible, without implying any sense of being recommended. This term is not intended to imply that the vendor's implementation must provide the option and the feature can be optionally enabled by the network operator/service provider. Rather, it means the vendor may optionally provide the feature and still claim conformance with the specification.
+
+# 6 System functional architecture
+
+This clause defines the functional architecture of multimedia information access systems in which the multimedia information access is triggered by tag-based identification. This architecture is based on the system components described in clause 6 of [ITU-T F.771] and shown in Figure 1. Compared with the high-level functional architecture, this system architecture decomposes each component into more detailed functional components.
+
+![Figure 1 – Functional architecture diagram showing the flow from an ID tag through an ID terminal and wide area public communication to ID resolution and multimedia information delivery functions.](b3baf3a29b67c7425d2562ddbc52f0cc_img.jpg)
+
+```
+
+graph LR
+    IDTag[ID tag  
+Identifier] --- NA[Narrow area communication  
+or optical data capture]
+    NA --- IDTerminal
+    subgraph IDTerminal [ID terminal]
+        IDTagRW[ID tag R/W]
+        MIDF[Multimedia information  
+discovery function]
+        MIHF[Multimedia information  
+handling function]
+        IDTagRW --- MIDF
+        MIDF --- MIHF
+    end
+    User((User)) <--> IDTerminal
+    IDTerminal --- WAPC((Wide area public  
+communication))
+    WAPC --- IDResolution[ID resolution function]
+    WAPC --- MIDelivery[Multimedia information  
+delivery function]
+    subgraph IDResolutionBox [ID resolution function]
+        SB1[Service broker  
+(ID resolution)]
+        IDR[ID resolver]
+        SB1 --- IDR
+    end
+    subgraph MIDeliveryBox [Multimedia information  
+delivery function]
+        SB2[Service broker  
+(Multimedia  
+information delivery)]
+        MIM[Multimedia information  
+manager]
+        SB2 --- MIM
+    end
+  
+```
+
+The diagram illustrates the functional architecture of a multimedia information access system. It starts with an **ID tag** containing an **Identifier**, which communicates via **Narrow area communication or optical data capture** to an **ID terminal**. The **ID terminal** contains three sub-components: **ID tag R/W**, **Multimedia information discovery function**, and **Multimedia information handling function**, connected in sequence. A **User** interacts with the **ID terminal** through a bidirectional arrow. The **ID terminal** connects to a central **Wide area public communication** hub. This hub then connects to two main functional blocks: the **ID resolution function** and the **Multimedia information delivery function**. The **ID resolution function** block contains a **Service broker (ID resolution)** and an **ID resolver**. The **Multimedia information delivery function** block contains a **Service broker (Multimedia information delivery)** and a **Multimedia information manager**.
+
+Figure 1 – Functional architecture diagram showing the flow from an ID tag through an ID terminal and wide area public communication to ID resolution and multimedia information delivery functions.
+
+**Figure 1 – Functional architecture**
+
+Figure 1 shows the logical functional architecture. This does not show the physical implementation of each high-level functional component. Examples of corresponding physical level architecture and their implementation are described in Appendix I.
+
+## 6.1 Functional components
+
+The system functional architecture for multimedia access triggered by tag-based identification is required to include the following components: ID tag, ID tag reader/writer (ID tag R/W, in short), multimedia information discovery function (MIDF), multimedia information handling function (MIHF), service broker (SB), ID resolver (IDR), and multimedia information manager (MIM). ID tag R/W, MIDF, and MIHF are sub-components included in an ID terminal. The IDR and SB are sub-components included in an ID resolution function. The MIM and SB are sub-components
+
+included in a multimedia information delivery function. Refer to clause 6 of [ITU-T F.771] regarding narrow area communication and wide area public communication.
+
+### **6.1.1 ID tag**
+
+An ID tag is required to store identifier(s) which can be read by an ID tag R/W in an ID terminal via narrow area communication. It can optionally store multimedia information and/or other data that is used in ID resolution and/or multimedia information presentation. Typical examples of ID tags are RFID, smartcard, infrared tag, barcode, 2D barcode, NFC listening device, etc.
+
+### **6.1.2 ID terminal**
+
+An ID terminal is required to be composed of three sub-components: 1) ID tag R/W; 2) multimedia information discovery function (MIDF); and 3) multimedia information handling function (MIHF). It can optionally contain multimedia information and/or other data. This data, such as a user's profile, can be used in ID resolution and/or multimedia information presentation.
+
+##### **6.1.2.1 ID tag R/W**
+
+An ID tag R/W is required to provide communication interfaces to an ID tag, and read a single or multiple identifier(s) as well as application data from the ID tag. After reading the identifiers, it sends their information to the MIDF. An ID terminal can optionally contain multiple ID tag R/Ws.
+
+##### **6.1.2.2 Multimedia information discovery function (MIDF)**
+
+A multimedia information discovery function (MIDF) is required to obtain the identifier from an ID tag R/W, and issues queries to the IDR or optionally the SB, depending on implementations, via wide area public communication. It uses the identifier as a query key in both cases. The ID resolver returns pointer information (e.g., URL) to access the MIM providing the multimedia information delivery services. After obtaining the pointer information, it sends the information to the MIHF.
+
+##### **6.1.2.3 Multimedia information handling function (MIHF)**
+
+A multimedia information handling function (MIHF) is required to provide a function to download multimedia information from the MIM, and presents the information to the user. It can optionally upload information to the MIM.
+
+### **6.1.3 Service broker (SB)**
+
+A service broker can optionally provide ID resolution services with the help of an ID resolver. When an ID terminal sends an identifier to the SB, it consults the ID resolver for resolution of the identifier, discovers the multimedia information access information and responds by sending the corresponding resolution result to the ID terminal. That is, the SB works as a proxy for the ID resolver.
+
+A SB can optionally provide multimedia information handling functions as well as the ID resolution proxy functions. That is, the SB can work as a multimedia information delivery proxy as well. Existence of the SB and its features depend on implementations.
+
+### **6.1.4 ID resolver (IDR)**
+
+An ID resolver is required to preserve the relationship between an identifier and its pointer information, such as URL, IP address and phone number, to access the multimedia information delivery function. It is required to provide the MIDF and SB with a translation service from the identifier into the pointer information.
+
+### **6.1.5 Multimedia information manager (MIM)**
+
+A multimedia information manager is required to receive a request from the MIHF in the ID terminal, and delivers multimedia information to it. It can optionally receive uploaded multimedia information from the MIHF.
+
+## 6.2 Protocols
+
+This architecture is required to be supported by the following standard protocols on the interfaces among the functional components described in clause 6.1. Figure 2 shows those interfaces.
+
+### 6.2.1 ID tag communication protocol
+
+The ID tag communication protocol is used by the ID terminal and ID tag for their data exchanges and allows the ID terminal to obtain an identifier from the ID tag.
+
+### 6.2.2 ID resolution protocol
+
+The ID resolution protocol is used by the MIDF and IDR for ID resolution services. The SB is required to use this protocol to interwork with the IDR.
+
+### 6.2.3 Service broker protocol
+
+The service broker protocol is a communication protocol used between the MIDF and SB, and also between the MIHF and SB.
+
+### 6.2.4 Multimedia information delivery protocol
+
+The multimedia information delivery protocol is a communication protocol used between the MIHF and MIM.
+
+![Figure 2: Interfaces between components in functional architecture. The diagram shows the functional architecture and protocols between an ID tag, ID terminal, and ID resolution function.](18442e4e239480f0c3c95b547aa8fde2_img.jpg)
+
+The diagram illustrates the functional architecture and protocols between three main components: ID tag, ID terminal, and ID resolution function.
+
+- ID tag:** Contains an **Identifier**.
+- ID terminal:** Contains three main functional blocks:
+  - ID tag R/W:** Connected to the ID tag via the **ID tag communication protocol** (Narrow area communication).
+  - Multimedia information discovery function:** Connected to the ID tag R/W and the Multimedia information handling function.
+  - Multimedia information handling function:** Connected to the Multimedia information discovery function and the Multimedia information manager.
+- ID resolution function:** Contains two main functional blocks:
+  - ID resolution function (top):** Contains a **Service broker** and an **ID resolver**. It is connected to the ID tag R/W via the **Service broker protocol** and to the Multimedia information discovery function via the **ID resolution protocol**.
+  - Multimedia information delivering function (bottom):** Contains a **Service broker** and a **Multimedia information manager**. It is connected to the Multimedia information handling function via the **Multimedia information delivery protocol** and to the Service broker via the **Service broker protocol**.
+
+The communication between the ID terminal and the ID resolution function is categorized as **Wide area public communication**.
+
+Figure 2: Interfaces between components in functional architecture. The diagram shows the functional architecture and protocols between an ID tag, ID terminal, and ID resolution function.
+
+Figure 2 – Interfaces between components in functional architecture
+
+## 6.3 General workflow
+
+This clause describes the high-level workflow that realizes multimedia access triggered by tag-based identification. This architecture is recommended to work according to the following workflow (see Figure 3).
+
+- 1) Identifier in the ID tag is obtained by the ID tag R/W in the ID terminal.
+- 2) ID tag R/W sends the identifier to the MIDF.
+
+- 3) MIDF sends the identifier to the IDR to discover pointer information of the multimedia information delivery function related to the identifier.  
+This communication can optionally be mediated by the SB. In this case, the MIDF requests the SB to make ID resolution (3-1), then the SB consults the IDR and retrieves the pointer information of the multimedia information delivery function (3-2).
+- 4) IDR resolves the identifier, finds the pointer information of the multimedia information delivery function related to the identifier, and then returns it to the MIDF.  
+This communication can also optionally be mediated by the SB. In this case, the IDR first sends a reply, including the pointer information to the SB (4-1), and then the SB forwards the reply to the MIDF (4-2).
+- 5) MIDF invokes the MIHF by forwarding the pointer information.
+- 6) MIHF sends the request of retrieving the multimedia information service to the MIM in the multimedia information delivery function.  
+This communication can optionally be mediated by SB. In this case, the MIHF requests to the SB (6-1), then the SB forwards the request to the MIM (6-2).
+- 7) MIM provides the multimedia information service to the MIHF.  
+This communication can also optionally be mediated by the SB. In this case, the MIM first provides the service to the SB (7-1), and then the SB mediates the service to the MIHF (7-2).
+- 8) MIHF plays the information and shows it to the user, or it uploads multimedia information to the MIM.
+
+Examples of this workflow are described in Appendix II.
+
+![Sequence diagram illustrating the general workflow of tag-based identification triggered multimedia information access. The diagram shows interactions between a User, ID tag, ID terminal (ID tag R/W, Multimedia information discovery function, Multimedia information handling function), ID resolution function (Service broker, ID resolver), and Multimedia information delivery function (Service broker, Multimedia information manager). The workflow is divided into three main phases: Tag-based identification process, ID resolution process, and Information presentation process. The steps are numbered 1 through 8, with optional steps in parentheses.](042733dc5e8e7f5f30b60adba3266cde_img.jpg)
+
+```
+
+sequenceDiagram
+    participant User
+    participant ID_tag as ID tag
+    participant ID_terminal as ID terminal
+    participant ID_resolution as ID resolution function
+    participant MIM as Multimedia information delivery function
+
+    ID_terminal -->> ID_tag : (1)
+    ID_tag -->> ID_terminal : (2)
+    ID_terminal -->> ID_resolution : (3-1)
+    ID_resolution -->> ID_resolution : (3-2)
+    ID_resolution -->> ID_resolution : (4)
+    ID_resolution -->> ID_resolution : (4-1)
+    ID_resolution -->> ID_resolution : (4-2)
+    ID_resolution -->> ID_terminal : (5)
+    ID_resolution -->> MIM : (6)
+    MIM -->> MIM : (6-1)
+    MIM -->> MIM : (6-2)
+    MIM -->> MIM : (7-1)
+    MIM -->> MIM : (7-2)
+    MIM -->> ID_resolution : (7)
+    ID_resolution -->> User : (8)
+  
+```
+
+Sequence diagram illustrating the general workflow of tag-based identification triggered multimedia information access. The diagram shows interactions between a User, ID tag, ID terminal (ID tag R/W, Multimedia information discovery function, Multimedia information handling function), ID resolution function (Service broker, ID resolver), and Multimedia information delivery function (Service broker, Multimedia information manager). The workflow is divided into three main phases: Tag-based identification process, ID resolution process, and Information presentation process. The steps are numbered 1 through 8, with optional steps in parentheses.
+
+**Figure 3 – General workflow of tag-based identification triggered multimedia information access**
+
+# Appendix I
+
+## Examples of physical level architecture
+
+(This appendix does not form an integral part of this Recommendation)
+
+### I.1 Configuration example of physical level architecture
+
+This appendix describes examples of physical level architecture based on the functional system architecture defined in this Recommendation. In the example shown in Figure I.1, the architecture consists of five types of physical components: 1) ID tags; 2) ID terminals (IDTs); 3) service broker (SB); 4) ID resolution servers (IRSs); and 5) multimedia information delivery servers (MIDSs). A wide area public network provides only end-to-end connection among IDTs, SBs, IRSs, and MIDSs, and it is divided into an IP network and other networks, such as mobile networks, which are interconnected by gateways. IDTs can be connected to other networks, and use the multimedia access triggered by tag-based identification (non-IP IDT).
+
+![Figure I.1: An example of physical level architecture. The diagram illustrates a system architecture where ID tags are used for narrow area communication with IDTs. These IDTs connect to a wide area public network, which is split into an IP network and a non-IP network. The IP network connects to IRSs and MIDSs. The non-IP network connects to a service broker (SB) and MIDSs connected to the non-IP network. A gateway (GW) connects the IP and non-IP networks.](410562339ce067fdc6fa41940c118658_img.jpg)
+
+The diagram shows the physical level architecture. On the left, two groups of 'ID tags' (represented by small rectangles with a black dot) are shown in 'Narrow area communication' with two types of 'IDTs' (ID Terminals). The top IDT is a standard mobile phone, and the bottom one is a 'non-IP IDT' (represented by a yellow phone icon). Both IDTs are connected to a 'Wide area public network'. This network is divided into an 'IP network' and a 'non-IP network', connected by a 'GW' (Gateway). The 'IP network' is connected to two 'IRS' (ID Resolution Servers) and two 'MIDS' (Multimedia Information Delivery Servers). The 'non-IP network' is connected to one 'SB' (Service Broker) and one 'MIDS connected to non-IP network'.
+
+Figure I.1: An example of physical level architecture. The diagram illustrates a system architecture where ID tags are used for narrow area communication with IDTs. These IDTs connect to a wide area public network, which is split into an IP network and a non-IP network. The IP network connects to IRSs and MIDSs. The non-IP network connects to a service broker (SB) and MIDSs connected to the non-IP network. A gateway (GW) connects the IP and non-IP networks.
+
+Figure I.1 – An example of physical level architecture
+
+### I.2 Components
+
+#### ID tag
+
+The ID tag contains identifier(s) of object, person and location. It may be RFID, RF/IR tag, barcode or 2D barcode. In usual cases, a single ID tag contains an identifier. However, a single ID tag may contain multiple identifiers. Alternatively, some ID tags are equipped with anti-collision communication or multiplexed communication mechanisms, which enable the tag reader/writer to communicate with multiple ID tags simultaneously.
+
+#### ID terminal (IDT)
+
+The ID terminal (IDT) implements the three functional components: ID tag reader/writer, multimedia information discovery function (MIDF), and multimedia information handling function
+
+(MIHF). Some IDTs, such as a PDA with a Wi-Fi facility and IP protocol stacks, may connect to an IP network directly, and also some other IDTs may connect to a non-IP network such as a mobile network which is interconnected to the IP network by a gateway. Additionally, Internet browsers are a popular implementation of an MIHF.
+
+#### **Service broker (SB)**
+
+The service broker (SB) works as a gateway or proxy of the ID terminal. It also works as a proxy of the MIDF.
+
+#### **ID resolution server (IRS)**
+
+The ID resolution server (IRS) realizes the function of ID resolver (IDR). The number space of identifiers is managed by multiple distributed ID resolution servers, which are connected to the IP network and cooperate with each other. To resolve an identifier into the pointer for the multimedia information delivery server, the resolution query is sent to multiple ID resolution servers (Figure I.4).
+
+#### **Multimedia information delivery server (MIDS)**
+
+The multimedia information delivery server (MIDS) realizes the function of multimedia information manager (MIM). Generally speaking, a single MIDS can provide multiple services. In this architecture, there may be a huge number of MIDSs, which are connected to an IP network or non-IP networks as peer nodes. Typical examples of the MIDSs are web servers, video/audio streaming servers, etc.
+
+#### **Narrow area communication**
+
+The narrow area communication connects ID tags and the ID tag R/W in the ID terminal. It has various types depending on the kinds of ID tag (see clause I.3 for examples). In most cases, the communication range of this network is less than a few metres.
+
+#### **Wide area public network**
+
+The wide area public network connects IDTs, IRSs, SBs and MIDSs. This architecture requires only end-to-end reliable connections among these components to the underlying wide area public network. In this architecture, the IP network is supposed to be the primary network, and other networks, such as mobile networks, will be interconnected by gateways. Some IDTs may be connected to the IP network directly, and some IDTs (for example, cellular phones) may be connected to other networks. In the same way, MIDSs may be connected to either IP or non-IP networks.
+
+### **I.3 Implementation examples of narrow area communication between ID tag and ID terminal**
+
+#### **I.3.1 Variations of narrow area communication between ID tag and ID tag R/W**
+
+Narrow area communication between ID tag and ID terminal is implemented by various communication technologies, mainly depending on the kinds of ID tag (Table I.1).
+
+**Table I.1 – Variations of narrow area communication between ID tag and ID tag R/W**
+
+| ID tag                 | ID tag R/W in ID terminal                      | Narrow area communication                                                                       |
+|------------------------|------------------------------------------------|-------------------------------------------------------------------------------------------------|
+| Passive RFID           | RFID R/W                                       | Contactless communication of RFID such as [b-ISO/IEC 18000-x]                                   |
+| Contactless smart card | Smart card R/W                                 | Contactless communication of smart card such as [b-ISO/IEC 14443-x], and NFC reader/writer mode |
+| Contact smart card     | Smart card R/W or smart card socket            | Contact communication of smart card such as [b-ISO/IEC 7816-x]                                  |
+| Barcode, 2D barcode    | Camera with image recognition or laser scanner | Image acquisition                                                                               |
+| Infrared tag           | Infrared transceiver                           | Infrared communication                                                                          |
+| Active RFID            | Base station                                   | Narrow area wireless communication such as Bluetooth, ZigBee, Wi-Fi and [b-ISO/IEC 18000-4]     |
+| NFC listening device   | NFC polling device                             | NFC reader/writer mode, NFC peer mode                                                           |
+
+#### I.3.2 Narrow area communication implementation using NFC
+
+For example, if we adopt near field communication (NFC) for the narrow area wireless communication network, the ID tag and ID terminal can take several novel forms. Figure I.2a takes the normal form of ID tag and ID terminal in a mobile phone. In Figure I.2b, the ID tag function is implemented by the reader/writer device in a mobile phone, and the identifier is read by an ID terminal implemented as a desktop PC. It is also possible to implement an ID tag and ID terminal in one device together.
+
+![Figure I.2: Examples of narrow area communication using NFC. The diagram is divided into two parts: (a) Reader-based configuration and (b) P2P-based configuration. In (a), an 'ID tag' (NFC card device) communicates with an 'ID terminal' (NFC polling device in NFC reader writer mode) via a 'Communication protocol in NFC forum reader writer mode'. In (b), an 'ID tag' (NFC listening device in peer mode or NFC listening device in card emulation mode) communicates with an 'ID terminal' (NFC polling device in peer mode or NFC polling device in reader writer mode) via a 'Communication protocol in NFC forum peer mode or reader writer mode'. The ID terminal in (b) is shown as a desktop PC with an 'ID tag R/W' device connected to it.](75f0cb39f1cd165dfe4a6aa6c4d9388d_img.jpg)
+
+a) Reader-based configuration
+
+b) P2P-based configuration
+
+Figure I.2: Examples of narrow area communication using NFC. The diagram is divided into two parts: (a) Reader-based configuration and (b) P2P-based configuration. In (a), an 'ID tag' (NFC card device) communicates with an 'ID terminal' (NFC polling device in NFC reader writer mode) via a 'Communication protocol in NFC forum reader writer mode'. In (b), an 'ID tag' (NFC listening device in peer mode or NFC listening device in card emulation mode) communicates with an 'ID terminal' (NFC polling device in peer mode or NFC polling device in reader writer mode) via a 'Communication protocol in NFC forum peer mode or reader writer mode'. The ID terminal in (b) is shown as a desktop PC with an 'ID tag R/W' device connected to it.
+
+**Figure I.2 – Examples of narrow area communication using NFC**
+
+#### I.3.3 Wired narrow area communication
+
+Narrow area communication includes wired or contact communication of smart card tags such as those described in [b-ISO/IEC 7816-x]. For example, if the [b-ISO/IEC 7816-x] reader/writer is implemented as an external device for an ID terminal, it takes the form illustrated in Figure I.3a. It is also possible to implement the reader/writer as an internal device for an ID terminal. Figure I.3b illustrates this configuration. Many 3G mobile terminals include a SIM socket and a small smart card is embedded into the socket. The system architecture in this Recommendation covers this type of system configurations. In this configuration, an ID terminal can obtain the identifier and use the
+
+multimedia information access at any time because it always carries ID tag(s) within it. On the other hand, it cannot change the identifier for the multimedia information access because it is fixed inside the ID terminal. If the user wants to change the identifier, he/she has to exchange the smart card manually.
+
+![Figure I.3 – Examples of wired narrow area communication. The diagram shows two scenarios: (a) External R/W and (b) Internal R/W. In (a), an ID tag is connected to an ID terminal via an external ISO 7816 interface. In (b), the ID tag is connected to an ID terminal via an internal ISO 7816 interface.](5cab96b2d23174c25919840ecd50aa48_img.jpg)
+
+The diagram illustrates two methods of wired narrow area communication between an ID terminal and an ID tag.
+
+**a) External R/W:** An ID tag (represented by a small rectangle) is connected to an ID terminal (represented by a yellow vertical rectangle) via an external ISO 7816 interface. A dashed arrow labeled 'Identifier' points from the ID tag to the ID terminal.
+
+**b) Internal R/W:** An ID tag is connected to an ID terminal via an internal ISO 7816 interface. A callout bubble labeled 'Inside of ID terminal' shows the internal connection between the ID tag and the ID terminal's internal ISO 7816 interface.
+
+Figure I.3 – Examples of wired narrow area communication. The diagram shows two scenarios: (a) External R/W and (b) Internal R/W. In (a), an ID tag is connected to an ID terminal via an external ISO 7816 interface. In (b), the ID tag is connected to an ID terminal via an internal ISO 7816 interface.
+
+**Figure I.3 – Examples of wired narrow area communication**
+
+### **I.4 Distributed implementation of ID resolution server**
+
+The total number of identifiers used in multimedia information access is expected to be very large. From the point of view of ID resolution query performance, and from the point of view of identifier space management, distributed implementation of IRSs is necessary. Figure I.4 illustrates the configuration of distributed IRSs in a tree structure and the ID resolution process on the basis of this configuration. In this example, identifiers are managed by multiple distributed IRSs, which are connected to the IP network and cooperate with each other. To resolve an identifier into a pointer to MIDS, the resolution query is sent to multiple IRSs. In this example, a query is processed as for domain name servers (DNSs) on the Internet. IRSs near to the root are responsible for resolving upper bits of identifiers, and IRSs near to leaf are responsible for resolving the lower bits. In Figure I.4, the grey part of identifier represents the bits managed by each IRS.
+
+![Diagram illustrating the cascade search for ID resolution. The left side shows a sequential process: 1st level resolution (ID code to IRS_B), 2nd level resolution (ID code to IRS_C), 3rd level resolution (ID code to IRS_D), and n-th level resolution (ID code to Address of MIDS, then Returning to ID Terminal). The right side shows a hierarchical tree structure starting from IRS_A (root IRS), branching into 2nd level IRS, then 3rd level IRS, and finally IRS_N (nth level IRS).](8fbdfc3d17fb1dae7b2d8f5a287fa9fc_img.jpg)
+
+The diagram illustrates the cascade search for ID resolution, showing a sequential process on the left and a hierarchical tree structure on the right.
+
+**Sequential Process (Left):**
+
+- 1st level resolution:** An ID code is processed to find IRS\_B.
+- 2nd level resolution:** The ID code is processed to find IRS\_C.
+- 3rd level resolution:** The ID code is processed to find IRS\_D.
+- n-th level resolution:** The ID code is processed to find the Address of MIDS, which then returns to the ID Terminal.
+
+**Hierarchical Tree Structure (Right):**
+
+- IRS\_A (root IRS):** The root of the hierarchy.
+- 2nd level IRS:** Branches from the root IRS\_A. One node is identified as IRS\_B.
+- 3rd level IRS:** Branches from the 2nd level IRS. One node is identified as IRS\_C.
+- IRS\_N (nth level IRS):** The final level in the hierarchy.
+
+Diagram illustrating the cascade search for ID resolution. The left side shows a sequential process: 1st level resolution (ID code to IRS\_B), 2nd level resolution (ID code to IRS\_C), 3rd level resolution (ID code to IRS\_D), and n-th level resolution (ID code to Address of MIDS, then Returning to ID Terminal). The right side shows a hierarchical tree structure starting from IRS\_A (root IRS), branching into 2nd level IRS, then 3rd level IRS, and finally IRS\_N (nth level IRS).
+
+**Figure I.4 – Cascade search for ID resolution**
+
+# Appendix II
+
+## Workflow examples for multimedia information access triggered by tag-based identification
+
+(This appendix does not form an integral part of this Recommendation)
+
+This appendix presents five typical examples of multimedia information access triggered by tag-based identification included in [ITU-T F.771]. For each example, its application scenario is described, and then the functional architecture and associated workflow are presented. Here, to make the description simple, the service broker is not used in the architecture and workflow.
+
+### II.1 Location-aware multimedia information service
+
+#### II.1.1 Application scenario
+
+Location-aware information services are among the most important applications of RFID. They provide location-aware information once the RFID and the active tag (beacon), which are attached and installed to the physical infrastructure (e.g., road), are read by passers-by and vehicles that try to access location-specific information.
+
+An identifier is assigned to the business information of a shop. The same content may be accessed by many methods, such as short message service (SMS), multimedia messaging service (MMS), wireless application protocol (WAP) and hypertext transfer protocol (HTTP), in several media types, such as text, image and video. The most appropriate method can be selected according to the capabilities of the ID terminal.
+
+#### II.1.2 System architecture
+
+The architecture in Figure II.1 implements the above scenario.
+
+![Figure II.1: Implementation architecture of location-aware information delivery services. The diagram shows the flow of information from an ID tag to a user via an ID terminal, involving an ID resolver and a multimedia information manager.](124c6108c63173818afb8ed49521e22d_img.jpg)
+
+The diagram illustrates the implementation architecture of location-aware information delivery services. It shows the following components and their interactions:
+
+- ID tag**: An external component that sends a signal (1) to the **ID tag R/W** module within the **ID terminal**.
+- ID terminal**: A central component containing three main modules:
+  - ID tag R/W**: Receives signal (1) from the ID tag and sends data to the **Multimedia information discovery function (MIDF)**.
+  - Multimedia information discovery function (MIDF)**: Sends data (2) to the **ID resolver (IDR)** and receives data (3) back. It also sends data (4) to the **Multimedia information handling function (MIHF)**.
+  - Multimedia information handling function (MIHF)**: Sends data (5) to the **Multimedia information manager (MIM)** and receives data (6) back.
+- ID resolver (IDR)**: An external component that interacts with the MIDF module.
+- Multimedia information manager (MIM)**: An external component that interacts with the MIHF module.
+- User**: A human user who receives information (7) from the **MIHF** module.
+
+Figure II.1: Implementation architecture of location-aware information delivery services. The diagram shows the flow of information from an ID tag to a user via an ID terminal, involving an ID resolver and a multimedia information manager.
+
+**Figure II.1 – Implementation architecture of location-aware  
+information delivery services**
+
+#### II.1.3 Workflow
+
+- 1) ID tag R/W obtains the identifier of the physical location (location identifier) from RFID or IR/RF beacon.
+- 2) Multimedia information discovery function (MIDF) sends the location identifier to ID resolver (IDR) to find the pointer and transfer protocol information of the associated multimedia information managers (MIMs).
+- 3) The pointer and transfer protocol of the MIMs are provided to the MIDF.
+- 4) MIDF sends the information of pointer and transfer protocol to the multimedia information handling function (MIHF).
+- 5) MIHF sends a multimedia information delivery service request to the MIMs which contain detailed information associated with the location identifier.
+- 6) The multimedia information associated with the location identifier in the tag is delivered to the MIHF in the ID terminal.
+- 7) User watches the multimedia information displayed by the ID terminal.
+
+### II.2 Multimedia information download via posters service
+
+#### II.2.1 Application scenario
+
+An RFID tag containing a movie identifier is attached to an advertisement poster for the movie. Multimedia information may be associated with this identifier, such as images, audio/music, movie segments, news or a portal web page for booking a ticket. If the user touches his/her mobile phone with an RFID reader on the RFID in the poster, he/she receives a list of the candidate services from the network. Then the user can pick up the desired information service by operating the mobile phone.
+
+#### II.2.2 System architecture
+
+The architecture in Figure II.2 implements this scenario.
+
+![Figure II.2: Implementation architecture and workflow of digital content delivery services using posters. The diagram shows the interaction between an ID tag, an ID terminal (containing ID tag R/W, MIDF, and MIHF), an ID resolver (IDR), and a Multimedia information manager (MIM), all leading to a User.](12de9b926df0384ec07702671827c9cd_img.jpg)
+
+The diagram illustrates the system architecture and workflow for digital content delivery services using posters. It shows the following components and their interactions:
+
+- ID tag**: Contains an RFID or barcode put on a poster, CD/DVD package, etc. It sends data (1) to the ID tag R/W.
+- ID terminal**: A central box containing three main functions:
+  - ID tag R/W**: Receives data (1) from the ID tag and sends data (2) to the MIDF.
+  - Multimedia information discovery function (MIDF)**: Sends data (2) to the ID resolver (IDR) and receives data (3) back. It also sends data (4) to the MIHF.
+  - Multimedia information handling function (MIHF)**: Sends data (5) to the Multimedia information manager (MIM) and receives data (6) back. It finally sends data (7) to the User.
+- ID resolver (IDR)**: Receives data (2) from the MIDF and sends data (3) back to the MIDF.
+- Multimedia information manager (MIM)**: Receives data (5) from the MIHF and sends data (6) back to the MIHF.
+- User**: Receives data (7) from the MIHF.
+
+Figure II.2: Implementation architecture and workflow of digital content delivery services using posters. The diagram shows the interaction between an ID tag, an ID terminal (containing ID tag R/W, MIDF, and MIHF), an ID resolver (IDR), and a Multimedia information manager (MIM), all leading to a User.
+
+**Figure II.2 – Implementation architecture and workflow of digital content delivery services using posters**
+
+#### **II.2.3 Workflow**
+
+- 1) ID tag R/W obtains the identifier in the poster or CD/DVD package from RFID or barcode.
+- 2) MIDF sends the identifier to the IDR to find the pointer and transfer protocol information of the associated MIMs.
+- 3) The pointer and transfer protocol information on MIMs is provided to the MIDF.
+- 4) MIDF sends the information, which includes the service identifier and the protocol of the MIM-*i* to the MIHF.
+- 5) The MIHF calls the multimedia information delivery service of the MIM-*i* containing the detailed information associated with the ID code.
+- 6) The multimedia information associated with the ID code is delivered to the MIHF in the ID terminal.
+- 7) User watches the multimedia information via the ID terminal.
+
+### **II.3 u-Museum**
+
+#### **II.3.1 Application scenario**
+
+u-Museum (ubiquitous museum) provides a multimedia information service for visitors, such as guidance for exhibited art pieces, navigation in the gallery, and advertisement information for museum shops. This service is implemented by RFID tags, active infrared tags, mobile terminals with an RFID reader and infrared receiver, multimedia database of exhibits, wired/wireless networks, and so on. In the u-Museum, an active infrared tag is put at the entrance gate of an exhibition room, and sends the identifier of the room. When a visitor with a mobile terminal walks through the gate, the terminal receives the identifier, retrieves the information of the exhibition in this room, and shows the information to the visitor. The exhibition room shows several pieces of fine art, and a tiny RFID tag is embedded in the explanation plate of each exhibit. The user can get precise information on the exhibits by touching the mobile terminal on the plate. When the visitor wants to go to the next exhibit, the system navigates the route according to the art tour route. If the visitor takes a wrong turn, the ID terminal receive an unexpected location identifier from an infrared tag. Then the ID terminal gives a warning to the visitor.
+
+#### **II.3.2 System architecture**
+
+The architecture in Figure II.3 implements this scenario.
+
+![Figure II.3: Implementation architecture and workflow of u-Museum services. The diagram shows an ID terminal containing an ID tag R/W, MIDF, and MIHF. An ID tag (RFID or IR/RF beacon) is used by the ID tag R/W. The MIDF interacts with an ID resolver (IDR) and a Multimedia information manager (MIM). The MIHF interacts with the MIM. A user interacts with the ID terminal.](5b8a756d9a71c35f17db8bcb90b438a3_img.jpg)
+
+```
+
+graph TD
+    IDTag[ID tag] -- (1) --> IDTagRW[ID tag R/W]
+    subgraph IDTerminal [ID terminal]
+        IDTagRW --> MIDF[Multimedia information discovery function MIDF]
+        MIDF -- (4) --> MIHF[Multimedia information handling function MIHF]
+    end
+    MIDF -- (2) --> IDR[ID resolver IDR]
+    IDR -- (3) --> MIDF
+    MIHF -- (5) --> MIM[Multimedia information manager MIM]
+    MIM -- (6) --> MIHF
+    User((User)) -- (7) --> IDTerminal
+
+```
+
+RFID or IR/RF beacon put on an exhibited object
+
+User
+
+Figure II.3: Implementation architecture and workflow of u-Museum services. The diagram shows an ID terminal containing an ID tag R/W, MIDF, and MIHF. An ID tag (RFID or IR/RF beacon) is used by the ID tag R/W. The MIDF interacts with an ID resolver (IDR) and a Multimedia information manager (MIM). The MIHF interacts with the MIM. A user interacts with the ID terminal.
+
+**Figure II.3 – Implementation architecture and workflow of u-Museum services**
+
+#### II.3.3 Workflow
+
+- 1) ID tag R/W obtains the identifier of the exhibited item in a gallery of u-Museum from the RFID or IR/RF beacon.
+- 2) MIDF sends the identifier to the IDR to find the pointer and transfer protocol information of the associated MIMs.
+- 3) The pointer and transfer protocol information of the MIMs is provided to the MIDF.
+- 4) MIDF sends the information to the MIHF.
+- 5) MIHF sends a multimedia information delivery service request to the MIMs.
+- 6) Multimedia information associated with the identifier is delivered to the MIHF in the ID terminal.
+- 7) User watches the multimedia information displayed by ID terminal.
+
+### II.4 Business card with personal identifier
+
+#### II.4.1 Application scenario
+
+Suppose that an identifier of a businessman is written on a business card. The identifier is associated to the latest contact address data record, including telephone number, fax number and e-mail address. His/her business client could get all the latest information from this identifier even after he/she has moved to another office or company.
+
+#### II.4.2 System architecture
+
+The architecture in Figure II.4 implements this scenario.
+
+![Figure II.4 – Implementation architecture and workflow of business card services. The diagram shows an ID terminal containing an ID tag R/W, MIDF, and MIHF. An ID tag with a barcode is scanned (1). MIDF sends the identifier to an IDR (2), which returns pointer and transfer protocol information (3). MIDF sends this info to MIHF (4). MIHF requests personal information from a MIM (5), which returns the info (6). Finally, the user receives the information (7).](e69b9188aa2c14ec6b21c83f711fef65_img.jpg)
+
+```
+
+graph LR
+    subgraph ID_terminal [ID terminal]
+        ID_tag_RW[ID tag R/W]
+        MIDF[Multimedia information discovery function MIDF]
+        MIHF[Multimedia information handling function MIHF]
+        ID_tag_RW --> MIDF
+        MIDF --> MIHF
+    end
+    ID_tag[ID tag  
+Barcode printed on a business card] -- (1) --> ID_tag_RW
+    MIDF <--> IDR[ID resolver IDR]
+    MIHF <--> MIM[Multimedia information manager MIM]
+    User((User)) -- (7) --> ID_terminal
+
+```
+
+Figure II.4 – Implementation architecture and workflow of business card services. The diagram shows an ID terminal containing an ID tag R/W, MIDF, and MIHF. An ID tag with a barcode is scanned (1). MIDF sends the identifier to an IDR (2), which returns pointer and transfer protocol information (3). MIDF sends this info to MIHF (4). MIHF requests personal information from a MIM (5), which returns the info (6). Finally, the user receives the information (7).
+
+**Figure II.4 – Implementation architecture and workflow of business card services**
+
+#### II.4.3 Workflow
+
+- 1) ID tag R/W obtains the identifier of a person from the barcode printed on a business card (personal identifier).
+- 2) MIDF sends the personal identifier to the IDR to find an associated personal information service.
+- 3) Pointer and transfer protocol information of the MIMs are provided to MIDF.
+- 4) MIDF sends the information to the MIHF.
+- 5) MIHF requests the personal information delivery service of the MIMs with the personal identifier. The MIHF also sends the login name and password information for user authentication.
+- 6) The personal information is delivered to the ID terminal according to the authentication result. If the user is authenticated as a valid business partner, the server will provide full contact information. If not, it will only provide an e-mail address.
+- 7) User receives the personal information displayed by the ID terminal.
+
+### II.5 Presence service with multimedia information
+
+#### II.5.1 Application scenario
+
+Imagine a theatre in which every visitor has a ticket with RFID, and every seat in the theatre contains an RFID reader. When the visitor enters the theatre and takes a seat, he/she puts the ticket on the RFID reader located in the arm of the seat. The reader reads the visitor identifier and automatically notifies the theatre office of the visitor status through the theatre management application.
+
+#### II.5.2 System architecture
+
+In this scenario, the configuration of the system looks somewhat different from that of the other scenarios (Figure II.5). However, this architecture is a simple variation of the general system architecture in Figure 1. ID terminal consists of two physical components: ID tag R/W and personal computer equipped with a presence management application. In this case, a visitor's ticket is the real-world entity identified by the ID tag, and the theatre manager in the theatre office is the user of the multimedia information access. The theatre management server manages the presence
+
+information in the theatre, and delivers, for example, theatre seat status information in 2D map format to the ID terminal.
+
+![Figure II.5 – Implementation architecture and workflow of the presence service in theatres. The diagram shows the interaction between an ID tag, an information terminal on the seat, an ID resolver (IDR), a theatre management server, and a theatre manager.](365b54f616aff249b4e6c0edafdcb9b3_img.jpg)
+
+The diagram illustrates the implementation architecture and workflow of the presence service in theatres. It shows the following components and their interactions:
+
+- ID tag**: A smart card or RFID for visitors ID.
+- Information terminal on the seat**: Contains an **ID tag R/W** and a **Presence management function** (which includes **Multimedia information discovery function (MIDF)** and **Multimedia information handling function (MIHF)**).
+- ID resolver (IDR)**: A server that resolves visitor identifiers.
+- Theatre management server**: A server that provides presence information.
+- Theatre manager**: A person who views the presence information.
+
+The workflow is as follows:
+
+- (1) ID tag R/W receives the ID tag.
+- (2) ID tag R/W sends the visitor identifier to the MIDF.
+- (3) MIDF sends the visitor identifier to the IDR.
+- (4) IDR sends the pointer and transfer protocol of the theatre management servers to the MIDF.
+- (5) MIDF sends the information to the MIHF, which requests the theatre management servers to obtain the presence information.
+- (6) The server replies with the presence information.
+- (7) MIHF updates the presence information and shows it to the theatre manager.
+
+Figure II.5 – Implementation architecture and workflow of the presence service in theatres. The diagram shows the interaction between an ID tag, an information terminal on the seat, an ID resolver (IDR), a theatre management server, and a theatre manager.
+
+**Figure II.5 – Implementation architecture and workflow of the presence service in theatres**
+
+#### II.5.3 Workflow
+
+- 1) ID tag R/W of the theatre seat obtains the visitor identifier from the visitor's ticket.
+- 2) ID tag R/W sends the visitor identifier to the MIDF in the presence management application.
+- 3) MIDF sends the visitor identifier to the IDR to find the theatre management servers associated with the visitor identifier.
+- 4) IDR informs the pointer and transfer protocol of the theatre management servers to the MIDF.
+- 5) MIDF sends the information to the MIHF, which, in turn, requests the theatre management servers to obtain the presence information.
+- 6) The server replies with the presence information.
+- 7) Multimedia information browser updates the presence information according to the received information, and shows it to the theatre manager.
+
+# Bibliography
+
+- [b-ISO/IEC 18000-x] ISO/IEC 18000-x-series (2008), *Information technology – Radio frequency identification for item management*.  
+<[http://www.iec.ch/searchpub/cur\\_fut.htm](http://www.iec.ch/searchpub/cur_fut.htm)>
+- [b-ISO/IEC 18000-4] ISO/IEC 18000-4 (2008), *Information technology – Radio frequency identification for item management – Part 4: Parameters for air interface communications at 2,45 GHz*.  
+<<http://webstore.iec.ch/webstore/webstore.nsf/artnum/041837>>
+- [b-ISO/IEC 14443-x] ISO/IEC 14443-x-series (in force), *Identification cards – Contactless integrated circuit cards – Proximity cards*.  
+<<http://webstore.iec.ch/webstore/webstore.nsf/artnum/039489>>  
+<<http://webstore.iec.ch/webstore/webstore.nsf/artnum/040281>>  
+<<http://webstore.iec.ch/webstore/webstore.nsf/artnum/040282>>  
+<<http://webstore.iec.ch/webstore/webstore.nsf/artnum/041675>>
+- [b-ISO/IEC 7816-x] ISO/IEC 7816-x-series (in force), *Identification cards – Integrated circuit cards*.  
+<[http://www.iec.ch/searchpub/cur\\_fut.htm](http://www.iec.ch/searchpub/cur_fut.htm)>
+
+
+
+# SERIES OF ITU-T RECOMMENDATIONS
+
+|                 |                                                                                             |
+|-----------------|---------------------------------------------------------------------------------------------|
+| Series A        | Organization of the work of ITU-T                                                           |
+| Series D        | General tariff principles                                                                   |
+| Series E        | Overall network operation, telephone service, service operation and human factors           |
+| Series F        | Non-telephone telecommunication services                                                    |
+| Series G        | Transmission systems and media, digital systems and networks                                |
+| <b>Series H</b> | <b>Audiovisual and multimedia systems</b>                                                   |
+| Series I        | Integrated services digital network                                                         |
+| Series J        | Cable networks and transmission of television, sound programme and other multimedia signals |
+| Series K        | Protection against interference                                                             |
+| Series L        | Construction, installation and protection of cables and other elements of outside plant     |
+| Series M        | Telecommunication management, including TMN and network maintenance                         |
+| Series N        | Maintenance: international sound programme and television transmission circuits             |
+| Series O        | Specifications of measuring equipment                                                       |
+| Series P        | Telephone transmission quality, telephone installations, local line networks                |
+| Series Q        | Switching and signalling                                                                    |
+| Series R        | Telegraph transmission                                                                      |
+| Series S        | Telegraph services terminal equipment                                                       |
+| Series T        | Terminals for telematic services                                                            |
+| Series U        | Telegraph switching                                                                         |
+| Series V        | Data communication over the telephone network                                               |
+| Series X        | Data networks, open system communications and security                                      |
+| Series Y        | Global information infrastructure, Internet protocol aspects and next-generation networks   |
+| Series Z        | Languages and general software aspects for telecommunication systems                        |

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+
+
+![ITU logo: a globe with the letters ITU inside, and a lightning bolt striking the globe.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg)
+
+ITU logo: a globe with the letters ITU inside, and a lightning bolt striking the globe.
+
+INTERNATIONAL TELECOMMUNICATION UNION
+
+# ITU-T
+
+TELECOMMUNICATION  
+STANDARDIZATION SECTOR  
+OF ITU
+
+# Y.1001
+
+(11/2000)
+
+SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE  
+AND INTERNET PROTOCOL ASPECTS
+
+Internet protocol aspects – General
+
+---
+
+**IP framework – A framework for convergence of  
+telecommunications network and IP network  
+technologies**
+
+ITU-T Recommendation Y.1001
+
+(Formerly CCITT Recommendation)
+
+---
+
+# ITU-T Y-SERIES RECOMMENDATIONS
+
+# GLOBAL INFORMATION INFRASTRUCTURE AND INTERNET PROTOCOL ASPECTS
+
+|                                                                    |                      |
+|--------------------------------------------------------------------|----------------------|
+| GLOBAL INFORMATION INFRASTRUCTURE                                  |                      |
+| General                                                            | Y.100–Y.199          |
+| Services, applications and middleware                              | Y.200–Y.299          |
+| Network aspects                                                    | Y.300–Y.399          |
+| Interfaces and protocols                                           | Y.400–Y.499          |
+| Numbering, addressing and naming                                   | Y.500–Y.599          |
+| Operation, administration and maintenance                          | Y.600–Y.699          |
+| Security                                                           | Y.700–Y.799          |
+| Performances                                                       | Y.800–Y.899          |
+| INTERNET PROTOCOL ASPECTS                                          |                      |
+| <b>General</b>                                                     | <b>Y.1000–Y.1099</b> |
+| Services and applications                                          | Y.1100–Y.1199        |
+| Architecture, access, network capabilities and resource management | Y.1200–Y.1299        |
+| Transport                                                          | Y.1300–Y.1399        |
+| Interworking                                                       | Y.1400–Y.1499        |
+| Quality of service and network performance                         | Y.1500–Y.1599        |
+| Signalling                                                         | Y.1600–Y.1699        |
+| Operation, administration and maintenance                          | Y.1700–Y.1799        |
+| Charging                                                           | Y.1800–Y.1899        |
+
+*For further details, please refer to the list of ITU-T Recommendations.*
+
+# **IP framework – A framework for convergence of telecommunications network and IP network technologies**
+
+## **Summary**
+
+In order to support the development of IP-related standards, this Recommendation identifies a framework to position the telecommunications aspects with respect to IP networks. This framework serves to identify and assist understanding the IP network issues, from the telecommunications point of view, with respect to the provision of seamless services to the user between IP networks and telecommunications networks in a convergence context.
+
+This Recommendation outlines a number of general architectures involving a mix of Telecommunication Network and Internet Protocol (IP) Network technologies. In this Recommendation, IP, the Internet Protocol, is considered in its role as a protocol purely associated with transporting connectionless packets.
+
+## **Source**
+
+ITU-T Recommendation Y.1001 was prepared by ITU-T Study Group 13 (2001-2004) and approved under the WTSA Resolution 1 procedure on 24 November 2000.
+
+## FOREWORD
+
+The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis.
+
+The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics.
+
+The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1.
+
+In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC.
+
+## NOTE
+
+In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency.
+
+## INTELLECTUAL PROPERTY RIGHTS
+
+ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process.
+
+As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database.
+
+© ITU 2001
+
+All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from ITU.
+
+# CONTENTS
+
+|                                                                                        | <b>Page</b> |
+|----------------------------------------------------------------------------------------|-------------|
+| 1 Introduction.....                                                                    | 1           |
+| 2 Scope and terms of reference.....                                                    | 1           |
+| 2.1 Scope.....                                                                         | 1           |
+| 2.2 Terms of reference .....                                                           | 2           |
+| 3 References (Informative) .....                                                       | 2           |
+| 3.1 ITU-T .....                                                                        | 2           |
+| 3.2 IETF .....                                                                         | 2           |
+| 4 Definitions .....                                                                    | 3           |
+| 5 Abbreviations.....                                                                   | 3           |
+| 6 General framework for an IP network .....                                            | 4           |
+| 6.1 General model.....                                                                 | 4           |
+| 6.2 Application (or Service) Model for IP Networks' Architecture.....                  | 5           |
+| 6.3 System (or functions) model for IP networks' architecture .....                    | 5           |
+| 6.3.1 Functions division on entities plane for system model.....                       | 6           |
+| 6.3.2 Functions division on logical plane for system model .....                       | 6           |
+| 6.3.3 End-to-end considerations .....                                                  | 8           |
+| 6.4 Technology model for IP network architecture .....                                 | 10          |
+| 7 Basic architectural principles.....                                                  | 10          |
+| 7.1 Principle 1 – vertical relationship .....                                          | 11          |
+| 7.2 Principle 2 – horizontal relationship.....                                         | 11          |
+| 7.3 Recursion .....                                                                    | 12          |
+| 8 Basic reference models .....                                                         | 12          |
+| 8.1 Layered protocol model .....                                                       | 12          |
+| 8.2 General protocol reference model – potential U-, C- and M-plane relationships..... | 13          |
+| 9 IP network overlay architecture .....                                                | 14          |
+| 10 Use of specific telecommunication bearers .....                                     | 15          |
+| 10.1 Use of a telecommunication bearer service between IP routers .....                | 16          |
+| 10.1.1 IP on ATM.....                                                                  | 16          |
+| 10.1.2 IP on SDH.....                                                                  | 16          |
+| 10.1.3 IP on frame relay .....                                                         | 16          |
+| 10.1.4 IP on leased lines .....                                                        | 16          |
+| 10.1.5 IP on WDM .....                                                                 | 16          |
+| 10.1.6 IP on satellite (VSAT or TV data channels).....                                 | 16          |
+
+|                                                                                   | <b>Page</b> |
+|-----------------------------------------------------------------------------------|-------------|
+| 10.2 Use of a telecommunication bearer service to access an IP network .....      | 16          |
+| 10.2.1 Use of circuit switched network .....                                      | 16          |
+| 10.2.2 Use of PSDN/frame relay .....                                              | 17          |
+| 10.2.3 Use of ATM/B-ISDN .....                                                    | 17          |
+| 10.2.4 Use of xDSL bitstreams.....                                                | 17          |
+| 10.2.5 Use of leased lines .....                                                  | 17          |
+| 10.2.6 Use of satellite (VSAT or TV data channels).....                           | 17          |
+| 10.2.7 Other access mechanisms .....                                              | 17          |
+| 11 Interworking within the underlying telecommunication infrastructure .....      | 18          |
+| 12 Telephony service interworking .....                                           | 18          |
+| 12.1 General considerations.....                                                  | 18          |
+| 12.2 Interworking functions.....                                                  | 20          |
+| 12.2.1 C-plane aspects .....                                                      | 20          |
+| 12.2.2 U-plane aspects.....                                                       | 20          |
+| 12.2.3 M-plane aspects .....                                                      | 21          |
+| 12.3 Interworking gateway architecture .....                                      | 21          |
+| 13 Native IP services interworking with services defined in ITU-T Recommendations | 22          |
+
+# **IP framework – A framework for convergence of telecommunications network and IP network technologies**
+
+# **1 Introduction**
+
+In order to support the development of IP-related standards, this Recommendation identifies a framework to position the telecommunications aspects with respect to IP networks. This framework serves to identify and assist understanding the IP network issues, from the telecommunications point of view, with respect to the provision of seamless services to the user between IP networks and telecommunications networks in a convergence context.
+
+This Recommendation outlines a number of general architectures involving a mix of Telecommunication Network and Internet Protocol (IP) Network technologies. In this Recommendation, IP, the Internet Protocol, is considered in its role as a protocol purely associated with transporting connectionless packets.
+
+# **2 Scope and terms of reference**
+
+## **2.1 Scope**
+
+The scope of this Recommendation includes:
+
+- a) the basic horizontal and vertical architectural principles that will be encountered in combining IP and telecommunications technologies in a variety of ways;
+- b) a generic protocol reference model and its application to an mixed IP/Telecommunication environment;
+- c) architectures for the use of the IP over telecommunications transport technologies;
+- d) other architectures involving the convergence, co-existence, or interworking between IP technologies and other telecommunications technologies.
+
+NOTE – This framework will cover both the integrated and non-integrated cases. Initially, it may be envisaged that the IP and non-IP technologies will co-exist separately, and/or only loosely coupled. Ultimately, it is envisaged that IP and non-IP (telecommunication) technologies will be converged into a single, optimally integrated IP telecommunication architecture.
+
+The scope embraces three possible types of scenarios involving networks and services based on ITU-T Recommendations, IETF RFCs/STDs, or other IP standards<sup>1</sup>:
+
+- e) ITU-T and ITU-R defined transport capabilities used to carry IP;
+- f) the use of IP to transport higher layer information whose semantics are defined in ITU-T Recommendations;
+
+---
+
+<sup>1</sup> Produced by a recognized standards development organization.
+
+- g) services<sup>2</sup> arising from standards defined by the Internet Engineering Task Force (IETF), or other recognized bodies, that are to be interworked with those defined in ITU-T Recommendations for the purposes of achieving seamless end-to-end user service.
+
+Cases f) and g) are particular examples of scope item d) above.
+
+## 2.2 Terms of reference
+
+The types of architecture described in this Recommendation are functional in nature, covering the following aspects:
+
+- a) general architectural concepts;
+- b) service/protocol layering;
+- c) service interworking; and
+- d) integration.
+
+# 3 References (Informative)
+
+The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is published regularly.
+
+## 3.1 ITU-T
+
+- ITU-T H.225.0 (2000), *Call signalling protocols and media stream packetization for packet-based multimedia communication systems*.
+- ITU-T H.245 (2000), *Control protocol for multimedia communications*.
+- ITU-T H.248 (2000), *Gateway control protocol*.
+- ITU-T H.323 (2000), *Packet-based multimedia communications systems*.
+- ITU-T I.555 (1997), *Frame relaying Bearer service interworking*.
+
+## 3.2 IETF
+
+- RFC 791      *Internet Protocol*.
+- RFC 1661     *The Point-to-Point Protocol (PPP)*.
+- RFC 1662     *PPP in HDLC-like Framing*.
+- RFC 2225     *Classical IP and ARP over ATM*.
+- RFC 2327     *SDP: Session Description Protocol*.
+- RFC 2364     *PPP over AAL5*.
+- RFC 2427     *Multiprotocol Interconnect over Frame Relay*.
+
+---
+
+<sup>2</sup> In this Recommendation the word "service" is used in two different ways according to the context. It is sometimes used in the architectural sense, as the abstract representation of features offered by a horizontal interface, or by a vertical (layer) interface. Alternatively, the word service is sometimes used in a more general sense, say to represent a particular telecommunications service, such the "telephone service" defined by E-series Recommendations.
+
+|          |                                                                 |
+|----------|-----------------------------------------------------------------|
+| RFC 2543 | <i>SIP: Session Initiation Protocol.</i>                        |
+| RFC 2615 | <i>PPP over SONET/SDH.</i>                                      |
+| RFC 2684 | <i>Multiprotocol Encapsulation over ATM Adaptation Layer 5.</i> |
+| RFC 2458 | <i>Toward the PSTN/Internet Inter-networking.</i>               |
+
+# 4 Definitions
+
+This Recommendation defines the following terms:
+
+**4.1 IP Service, IP Network Service:** A data transmission service in which the data that is transferred across the interface between the user and provider is in the form of IP (Internet Protocol) packets (sometimes called datagrams). The IP (Network) Service includes the service provided by using the IP Transfer Capabilities.
+
+**4.2 IP Network<sup>3</sup> (or IP Layer Network):** A network in which IP is used as a layer protocol.
+
+**4.3 IP Transfer Capability:** The set of network capabilities provided by the Internet Protocol (IP) layer. It may be characterized by the traffic contract as well as performance attributes supported by control and management functions of the underlying protocol layers. Examples of IP Transfer Capability include basic best effort IP packet delivery and the capability provided by Intserv, and Diffserv framework defined by the IETF.
+
+**4.4 IP Based Service:** The functions, facilities and capabilities implemented and executed over the IP Network Service. The IP based service utilizes the IP Transfer Capabilities offered by a network provider.
+
+**4.5 Circuit Switched Network (CSN):** A network in which a fixed bandwidth channel is established for, and dedicated to the duration of a communication session. The PSTN is an example of a CSN, where a circuit is established for the duration of a telephone call.
+
+# 5 Abbreviations
+
+|        |                                          |
+|--------|------------------------------------------|
+| AAL    | ATM Adaptation Layer                     |
+| AP     | Application Protocol                     |
+| ATM    | Asynchronous Transfer Mode               |
+| B-ISDN | Broadband ISDN                           |
+| CN     | Customer Network                         |
+| CRF    | Connection Related Function              |
+| CSN    | Circuit Switched Network                 |
+| IETF   | Internet Engineering Task Force          |
+| IN     | Intelligent Network                      |
+| INAP   | Intelligent Network Application Protocol |
+| IP     | Internet Protocol                        |
+
+---
+
+<sup>3</sup> The term "IP Network" is distinct from, and should not be confused with, the term "Internet". Many IP networks exist, each operated by different owners. Generally, individual IP networks may differ in scope and extent. They may be globally public (i.e. the Internet), totally private (i.e. with no open structure and without gateways to the Internet other private IP networks) or combinations of public and private networks (e.g. a privately run IP network with gateways and access to the Internet, but not necessarily vice versa).
+
+|        |                                     |
+|--------|-------------------------------------|
+| ISDN   | Integrated Services Digital Network |
+| ISP    | Internet Service Provider           |
+| IWU    | Interworking Unit                   |
+| LFC    | Local functional Capability         |
+| LLC    | Lower Layer Capability              |
+| N-ISDN | Narrowband ISDN                     |
+| PDH    | Plesiochronous Digital Hierarchy    |
+| PhDH   | Photonic Digital Hierarchy          |
+| POP    | Point of Presence                   |
+| PPP    | Point-to-Point Protocol             |
+| PSTN   | Public Switched Telephone Network   |
+| QoS    | Quality of Service                  |
+| SCP    | Service Control Point               |
+| SDH    | Synchronous Digital Hierarchy       |
+| SMS    | Service Management System           |
+| SS7    | Signalling System No. 7             |
+| SSP    | Service Switching Point             |
+| TE     | Terminal Equipment                  |
+| TN     | Telecommunications Network          |
+| UNI    | User Network Interface              |
+| WDM    | Wave Division Multiplexing          |
+
+# 6 General framework for an IP network
+
+This clause outlines some very general high level aspects.
+
+## 6.1 General model
+
+Architecture for IP networks may consist of three parts, Application (or Service) Model, System Model and Technology Model. Relationships among the three parts for IP Networks' Architecture are as shown in Figure 1.
+
+![Figure 1/Y.1001 – Model relationships diagram showing the relationships between the Application Model, System Model, and Technology Model.](b8661c6c54f72ecc7ff6cb05e47b2891_img.jpg)
+
+```
+
+graph TD
+    subgraph AM [Application Model]
+        UD[Users' Demands]
+    end
+    subgraph SM [System Model]
+        FS[Functions & Structure]
+    end
+    subgraph TM [Technology Model]
+        TS[Technical Specifications]
+    end
+
+    UD -- "Services support" --> FS
+    FS -- "Capability Requirement" --> UD
+    UD -- "Technical support" --> TS
+    TS -- "Standardization Requirement" --> UD
+    FS -- "Technical Requirement" --> TS
+    TS -- "Specifications support" --> FS
+
+```
+
+The diagram illustrates the relationships between three models in IP network architecture: the Application Model, the System Model, and the Technology Model. Each model is represented by an oval containing a rectangular box. The Application Model (top) contains 'Users' Demands'. The System Model (bottom left) contains 'Functions & Structure'. The Technology Model (bottom right) contains 'Technical Specifications'. Bidirectional arrows connect the boxes of the Application Model to both the System Model and the Technology Model. The arrows from the Application Model to the System Model are labeled 'Services support' (pointing down) and 'Capability Requirement' (pointing up). The arrows from the Application Model to the Technology Model are labeled 'Technical support' (pointing down) and 'Standardization Requirement' (pointing up). A bidirectional arrow connects the boxes of the System Model and the Technology Model, labeled 'Technical Requirement' (top) and 'Specifications support' (bottom). The identifier 'T1317280-00' is located at the bottom right of the diagram.
+
+Figure 1/Y.1001 – Model relationships diagram showing the relationships between the Application Model, System Model, and Technology Model.
+
+**Figure 1/Y.1001 – Model relationships**
+
+## 6.2 Application (or Service) Model for IP Networks' Architecture
+
+Application architecture for IP networks should reflect the relationship between customers and IP networks which provide services for the customers. It defines the applications role that an IP network should support, and describes the attributes of application services an IP network can provide for its users, such as media representation for various application services, Quality of Service (QoS) and requirements of traffic types. An application architecture model for IP Networks is shown in Figure 2.
+
+![Figure 2/Y.1001 – Application/service model. A 3D cube diagram showing the relationship between Traffic Type, QoS, and Media. The top face is divided into five traffic types: Conversational, Retrieval, Message, Distribution (controlled), and Distribution (uncontrolled). The front face is divided into QoS levels: Best Effort, Intserv, and Diffserv. The right face is divided into Media types: Voice, Data, and Video. The bottom face is divided into PHB types: CLS, GS, EF-PHB, and AF-PHB. A legend at the bottom left defines the abbreviations: AF (Assured Forwarding), CLS (Controlled Load Service), EF (Expedited Forwarding), GS (Guaranteed Service), and PHB (Per Hop Behaviour).](e9314c83043183351ed74908e9bf2f90_img.jpg)
+
+Figure 2/Y.1001 – Application/service model
+
+Legend:
+
+- AF Assured Forwarding
+- CLS Controlled Load Service
+- EF Expedited Forwarding
+- GS Guaranteed Service
+- PHB Per Hop Behaviour
+
+Figure 2/Y.1001 – Application/service model. A 3D cube diagram showing the relationship between Traffic Type, QoS, and Media. The top face is divided into five traffic types: Conversational, Retrieval, Message, Distribution (controlled), and Distribution (uncontrolled). The front face is divided into QoS levels: Best Effort, Intserv, and Diffserv. The right face is divided into Media types: Voice, Data, and Video. The bottom face is divided into PHB types: CLS, GS, EF-PHB, and AF-PHB. A legend at the bottom left defines the abbreviations: AF (Assured Forwarding), CLS (Controlled Load Service), EF (Expedited Forwarding), GS (Guaranteed Service), and PHB (Per Hop Behaviour).
+
+**Figure 2/Y.1001 – Application/service model**
+
+## 6.3 System (or functions) model for IP networks' architecture
+
+System model for IP networks' architecture should reflect the capabilities and construction of an IP network. In this case, system function components, interconnecting entities and relationships among them for supporting various application requirements by the IP network are described, such as nodes, links, terminals and their physical connection, location and label. Performance parameters for the system and its components should also be defined in this model.
+
+System model for IP networks' architecture can be described from, and functions divided into two planes (or directions): entities plane (horizontal direction) and logical plane (vertical direction).
+
+### 6.3.1 Functions division on entities plane for system model
+
+Functions on entities plane for System model of IP networks' architecture can be divided into three sections: core network, access network and customers' network. Each of them can be further divided in detail, for example, functions of a core network can be divided into two layers: IP layer function and telecommunication layer function. A reference configuration model for an IP Network is shown in Figure 3.
+
+![Figure 3/Y.1001 – IP network – reference framework diagram](042733dc5e8e7f5f30b60adba3266cde_img.jpg)
+
+The diagram illustrates the reference framework for an IP network, divided into three main sections: Customer Network, Access Network, and Backbone Network, separated by Reference Points (RP). The Customer Network on the left includes a mobile phone, a laptop, and a LAN. The Access Network in the middle contains IPAF (Internet Access Functions) and ANTF (Access Network Transport Functions). The Backbone Network on the right is divided into IP Capability (Best Effort, Intserv, Diffserv) and Broadband/NarrowBand services. A legend at the bottom left defines the abbreviations: ANTF for Access Network Transport Functions, IPAF for Internet Access Functions, and RP for Reference Point. The identifier T1317300-00 is located at the bottom right of the diagram.
+
+ANTF Access Network Transport Functions  
+IPAF Internet Access Functions  
+RP Reference Point
+
+T1317300-00
+
+Figure 3/Y.1001 – IP network – reference framework diagram
+
+**Figure 3/Y.1001 – IP network – reference framework**
+
+Examples of narrowband capabilities are 3.1 kHz audio channels, circuit and packet mode bearer services. Examples of broadband capabilities include Asynchronous Transfer Mode (ATM), channels from the Synchronous Digital Hierarchy (SDH) or Photonic Digital Hierarchy (PhDH), etc.
+
+NOTE – The figure does not attribute any particular distribution of functions between Customer Network and Access Network, nor between Access Network and Backbone Network. Further information regarding more detailed functionality distribution can be found in ITU-T Y.1231 – IP Access Network Architecture. The architecture details for the (Telecommunications) Access Network Transport Function can be found in ITU-T G.902 – Framework Recommendation on functional Access.
+
+### 6.3.2 Functions division on logical plane for system model
+
+Functions on logical plane for System model of IP networks' architecture can be divided into lower layer capabilities, IP layer capabilities and high layer capabilities, as shown in Figure 4.
+
+Information transfer between endpoints is provided by using IP packets. In the Internet, there is no fundamental difference in protocols at the IP layer used at the user-network interface, within the network and between other networks other than usage.
+
+The user-network or network-network interfaces of the IP network may not be located in the same points as the user-network or network-network interfaces of the underlying telecommunications network.
+
+Currently, protocols typically used at the interface between the customer and the IP service provider (e.g. dial PPP) or between IP service providers (e.g. BGP) may also be used in other parts of the network.
+
+Regarding the high layer capabilities, normally these are involved in the terminal equipment in the telecommunication environment. In the IP based environment, several types of high layer capabilities are involved in relation to the operation of the IP network itself, e.g. name server (e.g. DNS), authentication server (e.g. AAA) and address resolution server (e.g. DNS or DHCP), etc. One or more of these services may be provided by the customer or by providers other than the access provider.
+
+![Figure 4/Y.1001 – Basic configuration model of IP network. The diagram illustrates the architecture of an IP network, divided into Higher Layer Capabilities and Lower Layer Capabilities. The Higher Layer Capabilities section includes Directories, Databases, and Intelligent Agents, etc. The Lower Layer Capabilities section is further divided into the IP Layer network LLC and the Telecom. network LLC. The IP Layer network LLC contains Inter-router Control Capabilities and IP Capabilities. The Telecom. network LLC contains Broadband Capabilities, 64 kbit/s based ISDN Capabilities, and Inter-exchange Signalling Capabilities. The diagram also shows the interaction between the Customer Network (CN) and the Service Provider (TE or Service Provider) through Local Functional Capabilities (LFC). User-to-network signaling is shown between the TE CN and the LFC.](eefe19c5e14dc4d6c316b7f7fbb7d7d7_img.jpg)
+
+The diagram illustrates the basic configuration model of an IP network, organized into two main layers: Higher Layer Capabilities and Lower Layer Capabilities.
+
+- Higher Layer Capabilities of the IP Network:** This layer includes "Directories, Databases, Intelligent Agents, etc." and is connected to the Lower Layer Capabilities.
+- Lower Layer Capabilities of the IP Network:** This layer is divided into two main sections:
+  - IP Layer network LLC:** This section contains "Inter-router Control Capabilities" and "IP Capabilities".
+  - Telecom. network LLC:** This section contains "Broadband Capabilities", "64 kbit/s based ISDN Capabilities", and "Inter-exchange Signalling Capabilities".
+- External Components and Signaling:**
+  - TE CN (Terminal Equipment Customer Network):** Connected to the LFC (Local Functional Capabilities) on the left.
+  - TE or Service Provider:** Connected to the LFC (Local Functional Capabilities) on the right.
+  - User-to-network signaling:** Indicated by an arrow pointing from the TE CN towards the LFC.
+
+The diagram is labeled T1317310-00 in the bottom right corner.
+
+Figure 4/Y.1001 – Basic configuration model of IP network. The diagram illustrates the architecture of an IP network, divided into Higher Layer Capabilities and Lower Layer Capabilities. The Higher Layer Capabilities section includes Directories, Databases, and Intelligent Agents, etc. The Lower Layer Capabilities section is further divided into the IP Layer network LLC and the Telecom. network LLC. The IP Layer network LLC contains Inter-router Control Capabilities and IP Capabilities. The Telecom. network LLC contains Broadband Capabilities, 64 kbit/s based ISDN Capabilities, and Inter-exchange Signalling Capabilities. The diagram also shows the interaction between the Customer Network (CN) and the Service Provider (TE or Service Provider) through Local Functional Capabilities (LFC). User-to-network signaling is shown between the TE CN and the LFC.
+
+CN Customer Network  
+LFC Local Functional Capabilities  
+LLC Lower Layer capabilities
+
+**Figure 4/Y.1001 – Basic configuration model of IP network**
+
+### 6.3.3 End-to-end considerations
+
+Table 1a shows some typically traditional telecommunications (non-IP) services supported by typically traditional telecommunications (non-IP) access and backbone technologies. Each row in the table represents the provision of an end-to-end service. This table is not intended to be exhaustive, but to simply illustrate that, for any given service, the range of both access and backbone technologies is quite limited and is relatively homogeneous. At the interface between backbone domains, there is rarely a substantive change of technology or characteristics.
+
+**Table 1a/Y.1001 – Characteristics of non-IP services and non-IP technologies**
+
+| <b>End User Service</b>         | <b>Access Technology</b>                                                          | <b>Backbone Technology Domain 1</b> | <b>Backbone Technology Domain 2</b> | <b>Access Technology</b>                                                          | <b>End User Service</b>         |
+|---------------------------------|-----------------------------------------------------------------------------------|-------------------------------------|-------------------------------------|-----------------------------------------------------------------------------------|---------------------------------|
+| Voice Band and/or 3.1 kHz Audio | Analogue Loop<br>ISDN BRI/PRI<br>T1/E1 CAS<br>Cellular Mobile<br>VSAT<br>Cable TV | DS3/SDH/<br>SONET/ATM               | DS3/SDH/<br>SONET/ATM               | Analogue Loop<br>ISDN BRI/PRI<br>T1/E1 CAS<br>Cellular Mobile<br>VSAT<br>Cable TV | Voice Band and/or 3.1 kHz Audio |
+| 64 kbit/s Digital               | N-ISDN                                                                            | DS3/SDH/<br>SONET/ATM               | DS3/SDH/<br>SONET/ATM               | N-ISDN                                                                            | 64 kbit/s Digital               |
+| $N \times 64$ kbit/s Digital    | ISDN-PRI                                                                          | B-ISDN/SDH/<br>SONET/ATM            | B-ISDN/SDH/<br>SONET/ATM            | ISDN-PRI                                                                          | $N \times 64$ kbit/s Digital    |
+| Leased line                     | T1/E1                                                                             | DS3/SDH/<br>SONET/ATM               | DS3/SDH/<br>SONET/ATM               | T1/E1                                                                             | Leased line                     |
+| X.25                            | Various                                                                           | X.25                                | X.25                                | Various                                                                           | X.25                            |
+| Frame Relay                     | Various                                                                           | DS3/SDH/<br>SONET/ATM               | DS3/SDH/<br>SONET/ATM               | Various                                                                           | Frame Relay                     |
+
+With the introduction of IP services and the use of IP transport capabilities (which may provide capabilities which are "pure" IP, or which are enhanced by the IP transport capability making use of the underlying layer capabilities) as backbone technology this end-to-end alignment is radically reduced.
+
+Table 1b illustrates the support for Telecom Services by IP Networks, and Table 1c shows the support of IP services by telecom networks. In practice, elements of Table 1 and elements of Table 2 may apply, in different parts of an end-to-end path for a given communication. Consequently, the need for the development of interworking functions (IWFs) between various combinations of technology is greatly increased. IWFs may need to be applied at the network or user service level, or both, depending on the case under consideration.
+
+**Table 1b/Y.1001 – Traditional telecom services supported by IP networks**
+
+| End User Service | Access Technology                                                                              | Backbone Technology Domain 1 | Backbone Technology Domain 2 | Access Technology                                                                              | End User Service |
+|------------------|------------------------------------------------------------------------------------------------|------------------------------|------------------------------|------------------------------------------------------------------------------------------------|------------------|
+| 3.1 kHz Audio    | Analogue Loop<br>ISDN BRI/PRI<br>T1/E1 CAS<br>Cellular Mobile<br>VSAT<br>Cable TV<br>IP (Note) | IP (Note)                    | IP (Note)                    | Analogue Loop<br>ISDN BRI/PRI<br>T1/E1 CAS<br>Cellular Mobile<br>VSAT<br>Cable TV<br>IP (Note) | 3.1 kHz Audio    |
+| X.25             | Various                                                                                        | X.25<br>IP (Note)            | X.25<br>IP (Note)            | Various                                                                                        | X.25             |
+
+NOTE – It is understood that IP will run over a telecommunications network as shown in Table 1c.
+
+**Table 1c/Y.1001 – Telecom architectures supporting IP networks/services**
+
+| End User Service   | Access Technology                                                                                               | Backbone Technology Domain 1 (Note)                                                     | Backbone Technology Domain 2 (Note)                                                     | Access Technology                                                                                               | End User Service                                         |
+|--------------------|-----------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------|----------------------------------------------------------|
+| IP Best Effort     | Analogue Loop, Analogue Cellular, GSM, Coax, ISDN, SONET/SDH, ATM, FR, Gigabit Ethernet, Cable, Satellite, etc. | ATM, FR, DS3, SONET/SDH, Gigabit Ethernet, 100BaseT, FDDI, Cable, Satellite, etc.       | ATM, FR, DS3, SONET/SDH, Gigabit Ethernet, 100BaseT, FDDI, Cable, Satellite, etc.       | Analogue Loop, Analogue Cellular, GSM, Coax, ISDN, SONET/SDH, ATM, FR, Gigabit Ethernet, Cable, Satellite, etc. | IP (Best Effort, Controlled Load, Guaranteed Load, etc.) |
+| IP Controlled Load | Analogue Loop, Analogue Cellular, GSM, Coax, ISDN, SONET/SDH, ATM, FR, Gigabit Ethernet, Cable, Satellite, etc. | ATM, FR, DS3, SONET/SDH, Gigabit Ethernet, 100BaseT, FDDI, Cable, Satellite, etc.       | ATM, FR, DS3, SONET/SDH, Gigabit Ethernet, 100BaseT, FDDI, Cable, Satellite, etc.       | Analogue Loop, Analogue Cellular, GSM, Coax, ISDN, SONET/SDH, ATM, FR, Gigabit Ethernet, Cable, Satellite, etc. | IP (Best Effort, Controlled Load, Guaranteed Load, etc.) |
+| IP Guaranteed Load | Analogue Loop, Analogue Cellular, GSM, Coax, ISDN, SONET/SDH, ATM, FR, Gigabit Ethernet, Cable, Satellite, etc. | ATM, FR, DS3, SONET/SDH, Gigabit Ethernet, 100BaseT, FDDI, MPLS, Cable, Satellite, etc. | ATM, FR, DS3, SONET/SDH, Gigabit Ethernet, 100BaseT, FDDI, MPLS, Cable, Satellite, etc. | Analogue Loop, Analogue Cellular, GSM, Coax, ISDN, SONET/SDH, ATM, FR, Gigabit Ethernet, Cable, Satellite, etc. | IP (Best Effort, Controlled Load, Guaranteed Load, etc.) |
+
+NOTE – IP may or may not take advantage of the underlying features and facilities of the underlying technologies (e.g. ATM, Frame Relay, SDH/SONET, etc.).
+
+## 6.4 Technology model for IP network architecture
+
+The technology model for IP network architecture should consist of a series of technical standards or recommendations, describing configuration, interrelation and interaction of various components in an IP network as shown abstractly in Figure 5. The technology model comprises a diversified set of referenced standards or recommendations, for services, interfaces, equipment and interrelationships.
+
+![Diagram of the Technology Model for IP Network Architecture showing six layers: Terminal System, Quality of Service, Networking, Transmission, Information Modelling, Interworking, and Security, each with associated examples.](0f985b39edc1d52ba3600c438bc8f0a5_img.jpg)
+
+The diagram illustrates the Technology Model for IP Network Architecture. A vertical bar on the left is labeled "Technology Model for IP Network Architecture". To its right, under the heading "Referenced Standards", are six horizontal boxes representing different layers of the model. Each box is connected to a list of examples on the right:
+
+- Terminal System**: Host, phone, facsimile, video conference, WWW .....
+- Quality of Service**: Time delay, error, naturalness .....
+- Networking**: Router, sub-network, switching .....
+- Transmission**: Fiber, wired, wireless, satellite, access network .....
+- Information Modelling**: Voice, data, image, message .....
+- Interworking**: Network, service, management .....
+- Security**: Terminals, network, transmission, modelling, architectures, supporting services .....
+
+T1317320-00
+
+Diagram of the Technology Model for IP Network Architecture showing six layers: Terminal System, Quality of Service, Networking, Transmission, Information Modelling, Interworking, and Security, each with associated examples.
+
+**Figure 5/Y.1001 – Technology and Standards Model**
+
+# 7 Basic architectural principles
+
+Figure 6 shows the two most fundamental architectural relationships that can exist between one service (and its protocol) and another service (and its protocol). These relationships will occur, to a lesser or greater extent, in the IP/telecommunications convergence architectures which are described in this Recommendation. In some of the convergence architectures these principles will occur simultaneously and multiple times.
+
+![Diagram illustrating basic architectural principles. It shows four protocol blocks: Pa, Pb, Pq, and Pr. Pa and Pb are connected by a thick vertical double-headed arrow labeled 'Service Mapping & Encapsulation'. Pa and Pq are connected by a thick horizontal double-headed arrow labeled 'Service Mapping & Protocol Conversion'. Pb is below Pa, and Pq is to the right of Pa. Pr is above Pq. A dashed box encloses Pa, Pb, and Pq. Arrows point from labels to these relationships: 'Principle 1' points to the vertical arrow, 'Principle 2' points to the horizontal arrow, 'Peering Relationship' points to the horizontal arrow, and 'Layering Relationship' points to the vertical arrow. The text 'T1317330-00' is in the bottom right corner.](8fbdfc3d17fb1dae7b2d8f5a287fa9fc_img.jpg)
+
+Diagram illustrating basic architectural principles. It shows four protocol blocks: Pa, Pb, Pq, and Pr. Pa and Pb are connected by a thick vertical double-headed arrow labeled 'Service Mapping & Encapsulation'. Pa and Pq are connected by a thick horizontal double-headed arrow labeled 'Service Mapping & Protocol Conversion'. Pb is below Pa, and Pq is to the right of Pa. Pr is above Pq. A dashed box encloses Pa, Pb, and Pq. Arrows point from labels to these relationships: 'Principle 1' points to the vertical arrow, 'Principle 2' points to the horizontal arrow, 'Peering Relationship' points to the horizontal arrow, and 'Layering Relationship' points to the vertical arrow. The text 'T1317330-00' is in the bottom right corner.
+
+**Figure 6/Y.1001 – Basic architectural principles**
+
+## 7.1 Principle 1 – vertical relationship
+
+Principle 1, P1, shows the vertical relationship between protocols Pa and Pb. P1 is a layering relationship.
+
+With respect to P1, Pa is encapsulated within Pb, and uses the service offered by Pb. No fixed relationship between the actual protocols in the role of Pa and Pb can be assumed. A given protocol may be used in either a Pa or Pb role according to a specific context. For example, we may run X.25 protocol over the IP, or the IP over the X.25, according to particular requirements.
+
+## 7.2 Principle 2 – horizontal relationship
+
+P2 shows the horizontal relationship between Pa and Pq. P2 is a peering relationship.
+
+With respect to P2, where an end-to-end service is being provided by performing a concatenation/conversion between Pa and Pq, via some form of Interworking Unit (IWF) interposed within the path between Pa and Pq, the IWF terminates each of the protocols (Pa and Pq) and provides a mapping/matching between the service implementation provided by Pa to that provided by Pq. In the case of disparities between service implementations, some loss of features/capabilities will occur, to one or other or both of the end users.
+
+In the case where Pa and Pq are already end-to-end in nature and, thus, both terminate within end systems, the IWF in an end system may only be required to co-ordinate the events related to Pa and Pq for the purposes of achieving synchronization and synergy between services.
+
+NOTE – The notion of an "end" may also vary dependent on the viewpoint of the observer.
+
+## 7.3 Recursion
+
+Principles 1 and 2 may be repeated recursively, either within, or mutually between P1 and P2 structures. Some examples of this are shown in Figure 7.
+
+![Figure 7/Y.1001: Example of recursive application of principles 1 and 2. The diagram shows four hierarchical levels of recursive structure. Level 1: A single box containing two smaller boxes connected by a horizontal double-headed arrow. Level 2: A box containing two Level 1 structures connected by a horizontal double-headed arrow. Level 3: A box containing two Level 2 structures connected by a horizontal double-headed arrow. Level 4: A box containing two Level 3 structures connected by a horizontal double-headed arrow. The structures become increasingly complex with nested boxes and internal connections as the level increases. A reference code 'T1317340-00' is located at the bottom right of the diagram area.](dfe556fea00682b09a59427aaf72051c_img.jpg)
+
+Figure 7/Y.1001: Example of recursive application of principles 1 and 2. The diagram shows four hierarchical levels of recursive structure. Level 1: A single box containing two smaller boxes connected by a horizontal double-headed arrow. Level 2: A box containing two Level 1 structures connected by a horizontal double-headed arrow. Level 3: A box containing two Level 2 structures connected by a horizontal double-headed arrow. Level 4: A box containing two Level 3 structures connected by a horizontal double-headed arrow. The structures become increasingly complex with nested boxes and internal connections as the level increases. A reference code 'T1317340-00' is located at the bottom right of the diagram area.
+
+**Figure 7/Y.1001 – Example of recursive application of principles 1 and 2**
+
+# 8 Basic reference models
+
+## 8.1 Layered protocol model
+
+Generally, the process of utilizing the telecommunication bearers is hidden from the IP service users. However, standardized mappings are required for using the IP over each and every telecommunication protocol to be deployed.
+
+Figure 8 illustrates the layered protocol model for the provision of IP service. The area between the IP protocols and the actual telecommunication protocols (i.e. boxed area containing (a), (b), (c), etc.) represents the adaptation functions, mapping for QoS, and convergence/adaptation protocols (if necessary).
+
+This model only depicts the IP layer and below. Layers above the IP layer would be concerned with application requirements such as those required to select/negotiate and instantiate a specific voice encoding scheme for a voice service.
+
+In Figure 8, the following specific cases are shown:
+
+- Combination (a) IP Network scenario over FR (access)
+- Combination (b) IP Network scenario over FR (access) over ATM (backbone)
+- Combination (c) IP Network scenario over ATM (access)
+
+Combination (e) IP Network scenario over SDH/PhDH (existing mapping)
+
+Combination (g) IP Network scenario over Optical/WDM Transport Network or other physical layer technology, including cable TV.
+
+NOTE – Further mappings for combinations (d) and (f) may be required and are left for further study.
+
+The layered protocol architecture shown in Figure 8 is a straightforward example of the application of principle 1.
+
+![Figure 8/Y.1001 – Layered protocol model for IP network](3ae74a33759ae31781f484406db4feed_img.jpg)
+
+```
+
+  graph TD
+    IP["IP Present and Future"]
+    FR["Frame Relay"]
+    ATM["ATM (including existing AALs)"]
+    SDH["SDH/PDH"]
+    OTN["OTN or other Physical Layer Technologies (Wireless, Satellite, Cable TV, etc.)"]
+    Adapt["Additional adaptation functions for IP where required"]
+
+    IP -- "(a)" --> FR
+    IP -- "(b)" --> ATM
+    IP -- "(c)" --> SDH
+    IP -- "(d) (Note)" --> Adapt
+    FR --> ATM
+    FR --> SDH
+    ATM --> SDH
+    Adapt -- "(e)" --> SDH
+    Adapt -- "(f) (Note)" --> OTN
+    IP -- "(g)" --> OTN
+    SDH --> OTN
+  
+```
+
+NOTE – Further mapping methods may be required.
+
+T1317350-00
+
+**Figure 8/Y.1001 – Layered protocol model for IP network**
+
+Figure 8/Y.1001 – Layered protocol model for IP network
+
+### 8.2 General protocol reference model – potential U-, C- and M-plane relationships
+
+In addition to the hierarchical relationship shown in Figure 8, each protocol layer can be considered to have its user (U), control (C) and management (M) planes.
+
+An IP network operates via the IP layer protocol and its associated protocols (e.g. ICMP) with the telecommunication infrastructure as underlying supporting layers. IP was designed without a distinct concept of Control, User transport and Management planes, although it and its associated protocols do provide these functions. In some cases, these functions are implicitly included in the IP protocol. In cases where separate protocols for control and management of an IP network have been defined, these may be conveyed over IP. They may or may not be conveyed over the same logical and physical path as the customer's user data. This is an operational decision.
+
+Some components within the totality of equipment constituting an IP network will usually include control and management protocols not operating over, or directly associated with IP. This would apply, for example, to the equipment supporting the transport of IP.
+
+**ITU-T Y.1001 (11/2000)** 13
+
+In any event, where the two technologies converge there is a need to ensure appropriate mappings between the respective user (U), control (C) and management (M) planes. Mappings are required both between adjacent layers and between peer layers (in the case of service interworking). From this point of view, there is always a need to establish a protocol reference model (PRM) of an IP network to specify the relationship between an IP network and the telecommunication network U, C and M planes in order to adequately and comprehensively specify the overall service provision, control and management aspects. Figure 9 shows a PRM as applied to an IP network.
+
+![Figure 9/Y.1001 – Protocol reference model for an IP network. The diagram shows a 3D block diagram of a protocol reference model. It consists of several layers represented as rectangular blocks. At the top is a single block labeled 'Upper Layer – M'. Below it are two blocks side-by-side: 'Upper Layer – C' on the left and 'Upper Layer – U' on the right. These two blocks are connected by a dashed line, with a vertical line labeled 'C' on the left and a vertical line labeled 'U' on the right. Below these is a single, wider block labeled 'Layer 3 (IP)'. Below that is another block labeled 'Lower Layer/Sublayer – M'. At the bottom are two blocks side-by-side: 'Lower Layer/Sublayer – C' on the left and 'Lower Layer/Sublayer – U' on the right. Vertical lines connect the 'C' and 'U' blocks across the layers. A small label 'M' is on the right side of the 'Upper Layer – M' block, and 'T1317360-00' is at the bottom right corner of the diagram.](83852ec55d4802521a727926336bedab_img.jpg)
+
+Figure 9/Y.1001 – Protocol reference model for an IP network. The diagram shows a 3D block diagram of a protocol reference model. It consists of several layers represented as rectangular blocks. At the top is a single block labeled 'Upper Layer – M'. Below it are two blocks side-by-side: 'Upper Layer – C' on the left and 'Upper Layer – U' on the right. These two blocks are connected by a dashed line, with a vertical line labeled 'C' on the left and a vertical line labeled 'U' on the right. Below these is a single, wider block labeled 'Layer 3 (IP)'. Below that is another block labeled 'Lower Layer/Sublayer – M'. At the bottom are two blocks side-by-side: 'Lower Layer/Sublayer – C' on the left and 'Lower Layer/Sublayer – U' on the right. Vertical lines connect the 'C' and 'U' blocks across the layers. A small label 'M' is on the right side of the 'Upper Layer – M' block, and 'T1317360-00' is at the bottom right corner of the diagram.
+
+**Figure 9/Y.1001 – Protocol reference model for an IP network**
+
+# 9 IP network overlay architecture
+
+In this case IP is conveyed end-to-end, i.e. from IP host to IP host<sup>4</sup>, as shown in Figure 10. IP is overlaid on any underlying telecommunication protocol such as X.25, Frame Relay, ATM, ISDN, etc. Different telecommunication protocols may be used in different parts of the IP-based network itself, i.e. between routers, using the concepts of 8.1 and 8.2 for each inter-router link.
+
+<sup>4</sup> The term "IP host" is used as defined in RFC 1122 and 1123. According to the context, an IP host may be a computer, a terminal, or some type of specialized information appliance (e.g. phone, TV) or other equipment with network access for control/monitoring (e.g. heating and/or refrigeration equipment, household appliances, etc.).
+
+![Figure 10/Y.1001 – IP Network overlay architecture. The diagram shows two parts: a) and b). Part a) shows an IP Host connected to an IP Network, which is then connected to another IP Host. Part b) shows an IP Host connected to a TN Tx, which is connected to a Router, then to a TN Ty, then to a Router, then to an IWU, then to a Circuit Switched Network (CSN), and finally to an IP Host. The entire sequence in b) is enclosed in an oval labeled 'IP'.](5b8a756d9a71c35f17db8bcb90b438a3_img.jpg)
+
+a)
+
+b)
+
+IP
+
+IP Host
+
+IP Network
+
+IP Host
+
+IP Host
+
+TN Tx
+
+Router
+
+TN Ty
+
+Router
+
+IWU
+
+Circuit Switched Network (CSN)
+
+IP Host
+
+IP
+
+T1317370-00
+
+|       |                                              |
+|-------|----------------------------------------------|
+| IP    | Internet Protocol                            |
+| ISP   | Internet Service Provider                    |
+| IWU   | Interworking Unit                            |
+| POP   | Point of Presence                            |
+| TN Tx | Telecommunications Network technology type x |
+| TN Ty | Telecommunications Network technology type y |
+
+Figure 10/Y.1001 – IP Network overlay architecture. The diagram shows two parts: a) and b). Part a) shows an IP Host connected to an IP Network, which is then connected to another IP Host. Part b) shows an IP Host connected to a TN Tx, which is connected to a Router, then to a TN Ty, then to a Router, then to an IWU, then to a Circuit Switched Network (CSN), and finally to an IP Host. The entire sequence in b) is enclosed in an oval labeled 'IP'.
+
+**Figure 10/Y.1001 – IP Network overlay architecture**
+
+NOTE – The use of a CSN to access an IP POP is a special case, due to the dynamic/transient nature of the access arrangements and the use of IP and PSTN/ISDN addressing schemes. However, once the customer is connected to the POP the CSN case is the same as the other cases. This case is elaborated further in 10.2.1.
+
+# 10 Use of specific telecommunication bearers
+
+This clause outlines the use of specific telecommunication bearers. Two subcases may be identified:
+
+- a) use of a telecommunication bearer service between IP routers; and
+- b) use of a telecommunication bearer service to access an IP network.
+
+Typically, the Internet does not draw a hard distinction between user-network and network-network and intra-network in its use and choice of transmission bearer services. Thus, there may be little if any difference between the use of a leased line within an IP network and for the access to an IP network. Mostly, the difference lies in the policy (e.g. security, QoS) applied to routing and admission control. For example, although most people think of PSTN/ISDN dial-up as a method for accessing an IP network, there are cases in which PSTN/ISDN dial-up is used within an IP network to interconnect two routers.
+
+## **10.1 Use of a telecommunication bearer service between IP routers**
+
+### **10.1.1 IP on ATM**
+
+Currently, carriers utilize point-to-point ATM PVCs for interconnecting their IP routers using RFC 2684 ("Multiprotocol Encapsulation over ATM Adaptation Level 5") or RFC 2225 ("Classical IP and ARP over ATM AAL5") using either LLC/SNAP or direct encapsulation. ATM PVCs are used to provide interconnectivity and traffic engineering in the network. In the future, the integrated use of IP and ATM using MPLS is expected, enabling MPLS-enabled ATM switches to switch ATM cells on the basis of IP routing information.
+
+### **10.1.2 IP on SDH**
+
+In current practice, carriers support IP over SONET or SDH using RFC 2615 ("PPP over SONET/SDH").
+
+### **10.1.3 IP on frame relay**
+
+RFC 2427 ("Multiprotocol Interconnect over Frame Relay") is used to carry IP over Frame Relay between routers.
+
+### **10.1.4 IP on leased lines**
+
+Carriers use IP over TDM-based leased lines using RFC 1661 ("The Point-to-Point Protocol (PPP)") and RFC 1662 ("PPP in HDLC-like Framing").
+
+### **10.1.5 IP on WDM**
+
+This area is for further study.
+
+### **10.1.6 IP on satellite (VSAT or TV data channels)**
+
+This area is for further study.
+
+## **10.2 Use of a telecommunication bearer service to access an IP network**
+
+### **10.2.1 Use of circuit switched network**
+
+Figure 10 b) shows the extension of IP over a dial-in or dial-out Circuit Switched Network (CSN) connection used to gain access to an IP point-of-presence, as is currently provided by many Internet Service Providers (ISPs) today. A discrete three-stage process is required, firstly to establish the telecommunication bearer between the ISP POP and the end user, secondly to authenticate and authorize the dial-in (or dial-out) user and finally to route the IP packets.
+
+For voice support over such a dial-in service, the voice service is digitally encoded and conveyed as a payload of the IP network transparently to the CSN. This may be contrasted with the service interworking approach elaborated in clause 12.
+
+#### **10.2.1.1 Dial-in to the ISP POP**
+
+This case is relatively simple, being identical to existing dial-in access, i.e. set up the PSTN/ISDN connection to ISP, using a PSTN/ISDN number to access the interworking unit. Once the PSTN/ISDN connection is established the Point-to-Point Protocol (PPP) is invoked for the carriage of the IP containing the encoded voice information.
+
+#### **10.2.1.2 Dial-out from the ISP POP**
+
+Dial-out is supported in different ways by current ISPs. The user on the PSTN/ISDN is generally reachable from the user on the IP network using a standard IP address as the destination address for the PSTN/ISDN user. The user on the IP network may only be required to know the host name of the user on the PSTN/ISDN, thus letting DNS determine the correct IP address to use. In either case, the IWU has to determine the PSTN/ISDN address required for dial-out, from the IP address assigned to the PSTN/ISDN user (or the host name), through address translation/mapping mechanisms. For example, a static configuration could be used in the IWU to map the IP address to a PSTN/ISDN address, or a more dynamic method may be used (e.g. DNS, RADIUS, etc.). Standard mechanisms for performing this function have not been defined.
+
+Other cases may be possible, perhaps, by directly conveying the destination E.164 address across the IP network.
+
+Other requirements include locating a specific IWU optimally located for a given PSTN/ISDN destination.
+
+### **10.2.2 Use of PSDN/frame relay**
+
+Users access the Internet via frame relay by utilizing RFC 2427 ("Multiprotocol Interconnect over Frame Relay").
+
+### **10.2.3 Use of ATM/B-ISDN**
+
+Users typically access the Internet using ATM by utilizing RFC 2684, RFC 2364 or RFC 2225. Other methods are for further study.
+
+### **10.2.4 Use of xDSL bitstreams**
+
+Different DSL technologies may be used for accessing the Internet.
+
+In the case of ADSL and VDSL, users accessing the Internet use the same methods as listed for the use of ATM/B-ISDN.
+
+In the case of IDSL, HDSL, or SDSL, users accessing the Internet use RFC 1661 and RFC 1662.
+
+### **10.2.5 Use of leased lines**
+
+Uses accessing the Internet via leased lines use RFC 1661 ("Point-to-Point Protocol (PPP)") and RFC 1662 ("PPP in HDLC-like Framing").
+
+### **10.2.6 Use of satellite (VSAT or TV data channels)**
+
+For further study.
+
+### **10.2.7 Other access mechanisms**
+
+Other access mechanisms are in use or under investigation for access to the Internet. These include mobile wireless, fixed wireless, cable, Gigabit Ethernet (over fibre), cable TV or Satellite TV, etc. Some of these are not normally considered a telecommunication bearer services.
+
+# 11 Interworking within the underlying telecommunication infrastructure
+
+It is conceivable that interworking may be required/possible between two dissimilar telecommunication technologies without the presence of an intervening IP router, as shown in Figure 11.
+
+In the case where two different telecommunication network technologies are interworked, the interworking function may need to be aware of the adaptation/convergence protocols, and be prepared to provide appropriate interworking functions, if necessary, at the adaptation layer.
+
+Figure 11 shows the use of two different transport technologies, Tx and Ty, with corresponding adaptation functions AFx and AFy encapsulated within Tx and Ty. Two cases may be distinguished.
+
+In case 1, the adaptation protocol AFx is identical to AFy. In this case the interworking unit can transparently pass the adaptation protocol. In this case the adaptation protocol can simply be un-encapsulated from one side and re-encapsulated on the other side without change.
+
+Case 2 is required when AFx is not identical to AFy. In this case, the interworking unit must terminate both AFx and AFy and provide the necessary mapping functions. In this case, the adaptation protocol must be un-encapsulated and terminated on one side, and translated to a different adaptation protocol for subsequent encapsulation on the other.
+
+NOTE – ITU-T I.555 and ITU-T X.46 are examples of specifications for the interworking of two dissimilar telecommunication technologies, i.e. ATM and Frame Relay.
+
+![Diagram illustrating interworking within the underlying telecommunication infrastructure. The diagram shows an IP layer at the top, connected to two sides. On the left, a dashed box contains AFx and Tx. On the right, a dashed box contains AFy and Ty. In the center, a dashed box labeled 'Additional Interworking Functions' (marked with a circled 2) contains Tx and Ty. Dashed arrows indicate data flow between AFx and the central functions, and between AFy and the central functions. A solid line labeled with a circled 1 connects the IP layer to the central functions. The diagram is labeled T1317380-00 in the bottom right corner.](5132b3a97ac70fe4765c1e07e66b72b3_img.jpg)
+
+T1317380-00
+
+Diagram illustrating interworking within the underlying telecommunication infrastructure. The diagram shows an IP layer at the top, connected to two sides. On the left, a dashed box contains AFx and Tx. On the right, a dashed box contains AFy and Ty. In the center, a dashed box labeled 'Additional Interworking Functions' (marked with a circled 2) contains Tx and Ty. Dashed arrows indicate data flow between AFx and the central functions, and between AFy and the central functions. A solid line labeled with a circled 1 connects the IP layer to the central functions. The diagram is labeled T1317380-00 in the bottom right corner.
+
+**Figure 11/Y.1001 – Interworking within the underlying telecommunication infrastructure**
+
+Case 1 is an example of the application of principle 1. Case 2 is an example of both principle 2 and principle 1. Principle 2 applies to the interworking between the adaptation functions AFx and AFy, and principle 1 applies to the carriage of AFx over Tx and AFy over Ty.
+
+# 12 Telephony service interworking
+
+## 12.1 General considerations
+
+In this case interworking is achieved at the service level via an intermediate gateway or Interworking Unit (IWU) for the provision of an end-to-end voice service. All protocols terminate on the respective side of the Interworking Function (IWF). There is no end-to-end protocol in this case. The IP stack is terminated at the IWF. This is shown in Figure 12.
+
+![Figure 12/Y.1001 – Telephony service – basic interworking architecture. This diagram illustrates the basic interworking architecture for telephony service between an IP Network and a CSN (Circuit Switched Network). The IP Network is represented by a large oval containing two 'IP Host' boxes and an 'IP' label. The CSN is represented by a large oval containing two 'Phone' icons. An 'IWF' (Interworking Function) box connects the two networks. Four call scenarios are shown: (a) from an IP Host to a Phone; (b) from a Phone to an IP Host; (c) from an IP Host to another IP Host; and (d) from a Phone to another Phone. Arrows indicate the call direction. A legend at the bottom left states '→ = Call Direction'. The reference number 'T1317390-00' is at the bottom right.](7133ccf78043568ca62ecbcd43628a4a_img.jpg)
+
+Figure 12/Y.1001 – Telephony service – basic interworking architecture. This diagram illustrates the basic interworking architecture for telephony service between an IP Network and a CSN (Circuit Switched Network). The IP Network is represented by a large oval containing two 'IP Host' boxes and an 'IP' label. The CSN is represented by a large oval containing two 'Phone' icons. An 'IWF' (Interworking Function) box connects the two networks. Four call scenarios are shown: (a) from an IP Host to a Phone; (b) from a Phone to an IP Host; (c) from an IP Host to another IP Host; and (d) from a Phone to another Phone. Arrows indicate the call direction. A legend at the bottom left states '→ = Call Direction'. The reference number 'T1317390-00' is at the bottom right.
+
+**Figure 12/Y.1001 – Telephony service – basic interworking architecture**
+
+The connection patterns are classified into four scenarios (a) – (d), according to the point of origin and destination of the call, as follows:
+
+- (a) from audio capable IP Host on an IP network to a phone on the CSN (PSTN or ISDN);
+- (b) from a phone on a CSN to an audio capable IP Host on an IP network;
+- (c) from audio capable IP Host on an IP network to another audio capable IP Host on an IP network, via an intervening CSN;
+- (d) from a phone on a CSN to another a phone on a CSN, via an intervening IP network.
+
+The following figure outlines the mappings that are required in general for service interworking cases.
+
+![Figure 13/Y.1001 – Mappings for service interworking. This 3D block diagram shows the mapping between two service domains. The top layer consists of two 'IP-based applications' blocks. Below them are two 'Management Plane' blocks, which are connected to the applications by vertical double-headed arrows. Under the Management Planes are two 'Control Plane' and 'User Plane' blocks. The Control Planes are connected to the Management Planes by vertical double-headed arrows, and the User Planes are connected to the Management Planes by vertical double-headed arrows. Horizontal double-headed arrows connect the Management Planes, the Control Planes, and the User Planes. All these planes sit on top of a 'Physical Infrastructure' base. A legend at the bottom right states 'T1317400-00'.](a0739aaf13fa5a632d4faa830f6b2708_img.jpg)
+
+Figure 13/Y.1001 – Mappings for service interworking. This 3D block diagram shows the mapping between two service domains. The top layer consists of two 'IP-based applications' blocks. Below them are two 'Management Plane' blocks, which are connected to the applications by vertical double-headed arrows. Under the Management Planes are two 'Control Plane' and 'User Plane' blocks. The Control Planes are connected to the Management Planes by vertical double-headed arrows, and the User Planes are connected to the Management Planes by vertical double-headed arrows. Horizontal double-headed arrows connect the Management Planes, the Control Planes, and the User Planes. All these planes sit on top of a 'Physical Infrastructure' base. A legend at the bottom right states 'T1317400-00'.
+
+**Figure 13/Y.1001 – Mappings for service interworking**
+
+The horizontal arrows represent the application of principle 2. The vertical arrows represent the application of principle 1.
+
+## **12.2 Interworking functions**
+
+### **12.2.1 C-plane aspects**
+
+#### **12.2.1.1 Conversion of call connection procedure**
+
+In scenario (a), the functions are required for converting from the call connection procedure for the IP network section to that for the CSN section, to establish the end-to-end connection between the IP host and phone. The functions may be implemented in a gateway at the border between the IP network and the CSN.
+
+In scenario (b), the functions are required for converting from the call connection procedure for PSTN/ISDN CSN section to that for the IP network section to establish the end-to-end connection between phone and the IP host. The functions may be implemented at the border between the IP based network and the CSN.
+
+In scenarios (a), (b) and (c), the functions dealing with the call connection procedure for the IP network section may be required. The functions may be implemented at adapters attached to the IP host and/or in the gateway at the border between the IP network and the CSN.
+
+In scenarios (c) and (d), the functions for converting from the call connection procedure for the IP network section to that for CSN section, and vice versa, may be required or not, since in this case the call connection protocol may be transmitted transparently across the PSTN/ISDN/CSN or the IP network.
+
+#### **12.2.1.2 Numbering and addressing**
+
+In scenario (a), the address resolution functions are required to convert from the address used on the IP network section to that required for the CSN section for the designation of the called terminal.
+
+In scenario (b), the address resolution functions are required to convert from the address used on the CSN section to that required for the IP network section for the designation of the called terminal.
+
+In scenarios (a) and (c), PSTN directory functions may be required to designate the called terminals.
+
+### **12.2.2 U-plane aspects**
+
+#### **12.2.2.1 Conversion of voice coding methods**
+
+In each scenario, the functions are required for converting the voice encoding methods used for voice services over an IP network to those used for analogue voice over the PSTN or to those used for voice encoding over ISDN and digital trunk sections of PSTN, and vice versa.
+
+NOTE – The presence of different voice encoding systems is not peculiar to the IP network, and many existing ITU-T standards are applicable to this issue.
+
+#### **12.2.2.2 QoS for IP services**
+
+Specifications for various classes of IP service, characterized by different qualities of service will be required in order to select IP services suitable for specific types of application. Voice and other real-time sensitive applications are examples of applications which have specific QoS requirements. The specifications for these classes of IP service will include values for transmission delay and packet loss and other relevant QoS parameters.
+
+#### **12.2.2.3 Security**
+
+Specification for the provision of security in the IP network section will be required.
+
+### 12.2.3 M-plane aspects
+
+#### 12.2.3.1 Accounting
+
+IP networks do not include the concept of calls, and therefore have not included the concept of call-based accounting. Accounting capabilities that can support any and all scenarios in Figure 9 will need to be determined to support accounting principles and requirements defined by the appropriate ITU Study Group. Special attention may need to be given to permanent connection to PUSH services.
+
+## 12.3 Interworking gateway architecture
+
+Figure 14 shows a hypothetical and generic functional architecture of an interworking unit or gateway.
+
+Four functional components are shown:
+
+- a) Media Gateway (MG);
+- b) Media Gateway Controller (MGC);
+- c) Signalling Gateway (SG); and
+- d) Intelligent Databases (ID).
+
+The MG will handle the real-time operations associated with interworking, voice encoding conversion, etc. An MG terminates the circuit switched network (CSN) facilities (trunks, loops), packetizes the media stream, if it is not already packetized, and delivers packetized traffic to the IP network. It performs these functions in the reverse order for media streams flowing from the IP network to the CSN. The MG will interface with the CSN as per PSTN/ISDN requirements and specifications. The MG will interface with the IP network, using IP packets as the payload bearer, using Real-Time Protocol for voice transmission.
+
+The MGC will handle call control aspects associated with interworking. The MGC controls the operation of the Media Gateway function. Where these functions are packaged in separate devices, a protocol is needed between them. It is envisaged that the interconnection between the MGC and the MG will be over an IP network. The MGC interfaces to the IP network for the purposes of conveying call control information to peer entities on the IP network using either the IETF's Session Initiation Protocol (SIP) family of protocols, or the ITU-T's H.323 family of protocols (H.225, H.245, etc.). An MGC-MG control protocol is required and one candidate for this is H.248 (or its IETF equivalent).
+
+The SG will handle any necessary interactions between the interworking functions and the SS7 network. The SG is a signalling agent that receives/sends CSN native signalling at the border between the IP network and telecommunication network. In particular the SG function may relay, translate or terminate SS7 signalling in an SS7-Internet Gateway.
+
+The ID will be used to acquire any necessary information required, e.g. for credit card usage, 800 services, directory services, etc.
+
+Although all the illustrated functions may be packaged into one physical box, it is likely that the relative scale of operation of each of the component functions and the nature of multi-vendor equipment provision will result in the realization of separate physical units with the interconnection interfaces shown in Figure 14.
+
+The interworking functions between the IP network and the CSN require the application of principle 2. The other interfaces are various cases of the application of principle 1.
+
+![Figure 14/Y.1001 – Telephony gateway architecture diagram showing the interworking between IP Network, Interworking Functions, and CSN.](8c348bf9c2c81b018017ae1d19506a9a_img.jpg)
+
+The diagram illustrates the telephony gateway architecture, showing the interworking between the IP Network, Interworking Functions, and the CSN (Core Service Network).
+
+**IP Network:** Represented by a dashed line at the top left.
+
+**Interworking Functions:** A central block containing three main components:
+ 
+
+- Intelligent Databases:** Connected to the IP Network via a dashed line.
+- Signalling Gateway:** Connected to the Intelligent Databases via a solid line labeled **ID/SG** and **INAP**.
+- Media Gateway Controller:** Connected to the Signalling Gateway via a solid line labeled **SG/MGC**.
+
+**CSN:** Represented by a dashed line at the top right.
+
+**Connections and Interfaces:**
+
+- ID/MGC:** A solid line connection between the Intelligent Databases and the Media Gateway Controller.
+- MGC/MGC:** A dashed line connection between the Media Gateway Controller and the Media Gateway.
+- SS7 ISUP:** A solid line connection between the Signalling Gateway and the CSN.
+- RTP:** A solid line connection between the Media Gateway and the IP Network.
+- CSN Trunks:** A solid line connection between the Media Gateway and the CSN.
+
+**Media Gateway:** The bottom component, which handles the actual media flow between the IP Network and the CSN.
+
+**Legend:**
+
+- Solid lines with black dots represent control or signaling connections.
+- Dashed lines represent data or media connections.
+
+**Reference:** T1317410-00
+
+Figure 14/Y.1001 – Telephony gateway architecture diagram showing the interworking between IP Network, Interworking Functions, and CSN.
+
+**Figure 14/Y.1001 – Telephony gateway architecture**
+
+# 13 Native IP services interworking with services defined in ITU-T Recommendations
+
+In this case both the IP network and the telecommunication networks are used to provide services, via their inherent applications, in a complementary and synergistic fashion. For example, IP data services may be used in parallel with telecommunication voice and/or facsimile (fax) services. In this architecture, however, the establishment of the telecommunications-based services is triggered and controlled by a server on the IP network. Figure 15 depicts such an arrangement, where the actual services are deemed to exist in parallel universes but with coordinated or integrated control mechanisms.
+
+![Figure 15/Y.1001 – Parallel service architecture diagram](69b7bd65e85cdef6fdd7fb0a8194257c_img.jpg)
+
+The diagram illustrates a parallel service architecture between a Client(s) and a Server. The Client(s) side contains an IP App, Integration Functions, and a TN App. The Server side contains an IP App, Integration & Control Functions, and a TN App. The IP App on the client connects to the IP App on the server via an IP AP. The IP App on the client also connects to the Integration Functions, which in turn connect to the TN App. The Integration Functions on the client connect to the Integration & Control Functions on the server via an IP Network. The Integration & Control Functions on the server connect to the TN App on the server via a Non-IP Telecom Network. The TN App on the client connects to the TN App on the server via a TN AP. A legend at the bottom left defines IP App as IP Application and TN App as Telecommunication Network Application. The reference T1317420-00 is at the bottom right.
+
+Figure 15/Y.1001 – Parallel service architecture diagram
+
+**Figure 15/Y.1001 – Parallel service architecture**
+
+Figure 16 shows a specific example of such an arrangement. The synergy between the two networks is achieved by the link between the server, in this case an IP Host (for example a Web server) of the IP network and the IN Service Node (SN) or Service Control Point (SCP) of the telecommunication network. It is possible that the IP host and the SCP or SN will be co-resident on the IP network providing services to IP hosts and to the telecommunication network.
+
+The **PSTN/Internet Interworking (PINT)** activity developed jointly by IETF and ITU-T is an example of such an architecture. Other architectures are possible.
+
+![Figure 16/Y.1001 – PINT – An example of parallel service architecture diagram](474a819357587e34949a3e110ff19b30_img.jpg)
+
+The diagram shows a PINT architecture. On the left, two IP Terminals connect to an IP Network. Inside the IP Network is a Web Server. The Web Server connects to three points: A (to an SN), B (to an SCP), and E (to an SMS). The SCP connects to an SS7 network, which in turn connects to an SSP. The SMS connects to an SN, which also connects to an SSP. The SS7 network connects to the SSP. The SSP connects to two Phone/Fax devices. A legend at the bottom left defines the components: Gateway function (shaded box), IN (Intelligent Network), SCP (Service Control Point), SMS (Service Management System), SN (Service Node), SS7 (Signalling System No. 7), and SSP (Service Switching Point). The reference T1317440-00 is at the bottom right.
+
+Figure 16/Y.1001 – PINT – An example of parallel service architecture diagram
+
+**Figure 16/Y.1001 – PINT – An example of parallel service architecture**
+
+The interfaces A, B and E correspond to those defined in RFC 2458 "Toward the PSTN/Internet Inter-networking".
+
+# SERIES OF ITU-T RECOMMENDATIONS
+
+|                 |                                                                                                                                |
+|-----------------|--------------------------------------------------------------------------------------------------------------------------------|
+| Series A        | Organization of the work of ITU-T                                                                                              |
+| Series B        | Means of expression: definitions, symbols, classification                                                                      |
+| Series C        | General telecommunication statistics                                                                                           |
+| Series D        | General tariff principles                                                                                                      |
+| Series E        | Overall network operation, telephone service, service operation and human factors                                              |
+| Series F        | Non-telephone telecommunication services                                                                                       |
+| Series G        | Transmission systems and media, digital systems and networks                                                                   |
+| Series H        | Audiovisual and multimedia systems                                                                                             |
+| Series I        | Integrated services digital network                                                                                            |
+| Series J        | Transmission of television, sound programme and other multimedia signals                                                       |
+| Series K        | Protection against interference                                                                                                |
+| Series L        | Construction, installation and protection of cables and other elements of outside plant                                        |
+| Series M        | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits |
+| Series N        | Maintenance: international sound programme and television transmission circuits                                                |
+| Series O        | Specifications of measuring equipment                                                                                          |
+| Series P        | Telephone transmission quality, telephone installations, local line networks                                                   |
+| Series Q        | Switching and signalling                                                                                                       |
+| Series R        | Telegraph transmission                                                                                                         |
+| Series S        | Telegraph services terminal equipment                                                                                          |
+| Series T        | Terminals for telematic services                                                                                               |
+| Series U        | Telegraph switching                                                                                                            |
+| Series V        | Data communication over the telephone network                                                                                  |
+| Series X        | Data networks and open system communications                                                                                   |
+| <b>Series Y</b> | <b>Global information infrastructure and Internet protocol aspects</b>                                                         |
+| Series Z        | Languages and general software aspects for telecommunication systems                                                           |

marked/Y/T-REC-Y.1261-200212-I_PDF-E/raw.md

@@ -0,0 +1,706 @@
+
+
+![ITU logo: a globe with the letters ITU inside, and a lightning bolt striking the globe.](2dfa6ac3edfe874f68aa0cbccaa42322_img.jpg)
+
+ITU logo: a globe with the letters ITU inside, and a lightning bolt striking the globe.
+
+INTERNATIONAL TELECOMMUNICATION UNION
+
+**ITU-T**
+
+TELECOMMUNICATION  
+STANDARDIZATION SECTOR  
+OF ITU
+
+**Y.1261**
+
+(12/2002)
+
+SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE  
+AND INTERNET PROTOCOL ASPECTS
+
+Internet protocol aspects – Architecture, access, network  
+capabilities and resource management
+
+# --- **Service requirements and architecture for voice services over Multi-Protocol Label Switching**
+
+ITU-T Recommendation Y.1261
+
+---
+
+## ITU-T Y-SERIES RECOMMENDATIONS GLOBAL INFORMATION INFRASTRUCTURE AND INTERNET PROTOCOL ASPECTS
+
+|                                                                           |                      |
+|---------------------------------------------------------------------------|----------------------|
+| GLOBAL INFORMATION INFRASTRUCTURE                                         |                      |
+| General                                                                   | Y.100–Y.199          |
+| Services, applications and middleware                                     | Y.200–Y.299          |
+| Network aspects                                                           | Y.300–Y.399          |
+| Interfaces and protocols                                                  | Y.400–Y.499          |
+| Numbering, addressing and naming                                          | Y.500–Y.599          |
+| Operation, administration and maintenance                                 | Y.600–Y.699          |
+| Security                                                                  | Y.700–Y.799          |
+| Performances                                                              | Y.800–Y.899          |
+| INTERNET PROTOCOL ASPECTS                                                 |                      |
+| General                                                                   | Y.1000–Y.1099        |
+| Services and applications                                                 | Y.1100–Y.1199        |
+| <b>Architecture, access, network capabilities and resource management</b> | <b>Y.1200–Y.1299</b> |
+| Transport                                                                 | Y.1300–Y.1399        |
+| Interworking                                                              | Y.1400–Y.1499        |
+| Quality of service and network performance                                | Y.1500–Y.1599        |
+| Signalling                                                                | Y.1600–Y.1699        |
+| Operation, administration and maintenance                                 | Y.1700–Y.1799        |
+| Charging                                                                  | Y.1800–Y.1899        |
+
+*For further details, please refer to the list of ITU-T Recommendations.*
+
+# **ITU-T Recommendation Y.1261**
+
+# **Service requirements and architecture for voice services over Multi-Protocol Label Switching**
+
+## **Summary**
+
+This Recommendation describes service requirements and architecture for transport of Voice Services over MPLS networks.
+
+Voice Services over MPLS networks include a family of protocols that may be supported over MPLS, including Voice over IP (as specified by IETF), Voice over MPLS (as specified by MPLS Forum) and I.366.2 Voice Trunking Format (based on ITU-T Rec. I.366.2 adapted for MPLS).
+
+Possible approaches for transporting Voice Services over MPLS are provided in Appendix II.
+
+Detailed protocol specifications are subject of other Recommendations.
+
+###### **Source**
+
+ITU-T Recommendation Y.1261 was prepared by ITU-T Study Group 13 (2001-2004) and approved under the WTSA Resolution 1 procedure on 14 December 2002.
+
+## FOREWORD
+
+The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis.
+
+The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics.
+
+The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1.
+
+In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC.
+
+## NOTE
+
+In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency.
+
+## INTELLECTUAL PROPERTY RIGHTS
+
+ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process.
+
+As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database.
+
+© ITU 2003
+
+All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU.
+
+## CONTENTS
+
+|   |                                                                                                                                           | Page |
+|---|-------------------------------------------------------------------------------------------------------------------------------------------|------|
+| 1 | Scope .....                                                                                                                               | 1    |
+| 2 | References.....                                                                                                                           | 1    |
+|   | 2.1 Normative references.....                                                                                                             | 1    |
+|   | 2.2 Informative references.....                                                                                                           | 2    |
+| 3 | Definitions .....                                                                                                                         | 2    |
+| 4 | Abbreviations.....                                                                                                                        | 3    |
+| 5 | Architecture .....                                                                                                                        | 3    |
+|   | 5.1 Voice Services over MPLS logical service reference model .....                                                                        | 4    |
+|   | 5.2 Voice services over MPLS Reference Architecture.....                                                                                  | 5    |
+| 6 | Requirements for Voice Services over MPLS.....                                                                                            | 5    |
+|   | 6.1 General service requirements .....                                                                                                    | 5    |
+|   | 6.2 User plane requirements .....                                                                                                         | 6    |
+|   | 6.3 User plane requirements for combined audio and video service.....                                                                     | 6    |
+|   | 6.4 Control plane requirements .....                                                                                                      | 7    |
+|   | 6.5 Management plane requirements.....                                                                                                    | 7    |
+| 7 | Voice Services over MPLS interworking requirements .....                                                                                  | 7    |
+|   | 7.1 Voice Services over MPLS Interworking requirements with Voice over IP.....                                                            | 7    |
+|   | 7.2 Voice Services over MPLS interworking requirements with Voice over ATM .....                                                          | 7    |
+|   | 7.3 Voice Services over MPLS interworking requirements with Voice over Frame Relay.....                                                   | 7    |
+|   | 7.4 Voice Services over MPLS interworking requirements with PSTN/ISDN....                                                                 | 7    |
+|   | 7.5 Voice Services over MPLS Interworking requirements with mobile access networks .....                                                  | 8    |
+|   | Appendix I – Voice over Packet Protocol architectures .....                                                                               | 8    |
+|   | I.1 Voice over Frame Relay .....                                                                                                          | 8    |
+|   | I.1.1 FR reference model and service description .....                                                                                    | 8    |
+|   | I.1.2 Multiplexing .....                                                                                                                  | 9    |
+|   | I.1.3 Voice over Frame Relay user plane protocol stack.....                                                                               | 10   |
+|   | I.2 Voice over ATM as described in AAL type 2 Service Specific Convergence Sublayer for trunking [9].....                                 | 10   |
+|   | I.2.1 User plane protocol stack for Voice over ATM as described in AAL type 2 Service-Specific Convergence Sublayer for trunking [9]..... | 11   |
+|   | I.3 Voice over IP .....                                                                                                                   | 11   |
+
+|                                                                               | <b>Page</b> |
+|-------------------------------------------------------------------------------|-------------|
+| Appendix II – Alternate solutions for Voice Services over MPLS.....           | 12          |
+| II.1    Voice over ATM.....                                                   | 12          |
+| II.2    Voice over IP.....                                                    | 13          |
+| II.3    I.366.2 Voice Trunking format over MPLS .....                         | 13          |
+| II.4    Voice over MPLS .....                                                 | 13          |
+| II.5    Summary of different solutions for Voice Services over MPLS.....      | 14          |
+| Appendix III – BICC architecture.....                                         | 14          |
+| Appendix IV – Examples of Voice Services over MPLS deployment scenarios ..... | 15          |
+
+# ITU-T Recommendation Y.1261
+
+# Service requirements and architecture for voice services over Multi-Protocol Label Switching
+
+# 1 Scope
+
+The scope of this Recommendation is to describe services requirements and architecture for transport of Voice Services over MPLS networks.
+
+Voice Services over MPLS networks include a family of protocols that may be supported over MPLS, including Voice over IP (as specified by IETF), Voice over MPLS (as specified by MPLS Forum) and I.366.2 Voice Trunking Format (based on ITU-T Rec. I.366.2 adapted for MPLS).
+
+An overview of several possible approaches that have been proposed as the basis for the family of protocols for transporting Voice services over MPLS is provided in Appendix II. Nothing in this Recommendation precludes the progression of all these protocols for the transport of Voice Services over MPLS.
+
+# 2 References
+
+The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation.
+
+## 2.1 Normative references
+
+- [1] ITU-T Recommendation G.711 (1988), *Pulse code modulation (PCM) of voice frequencies*.
+- [2] ITU-T Recommendation G.723.1 (1996), *Speech coders: Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 kbit/s*.
+- [3] ITU-T Recommendation G.726 (1990), *40, 32, 24, 16 kbit/s Adaptive Differential Pulse Code Modulation (ADPCM)*.
+- [4] ITU-T Recommendation G.729 (1996), *Coding of speech at 8 kbit/s using conjugate-structure-algebraic-code-excited linear prediction (CS-ACELP)*.
+- [5] ITU-T Recommendation I.361 (1999), *B-ISDN ATM layer specification*.
+- [6] ITU-T Recommendation I.363.1 (1996), *B-ISDN Adaptation Layer specification: Type 1 AAL*.
+- [7] ITU-T Recommendation I.363.2 (2000), *B-ISDN Adaptation Layer specification: Type 2 AAL*.
+- [8] ITU-T Recommendation I.363.5 (1996), *B-ISDN Adaptation Layer specification: Type 5 AAL*.
+- [9] ITU-T Recommendation I.366.2 (2000), *AAL type 2 service specific convergence sublayer for narrow-band services*.
+- [10] ITU-T Recommendation I.610 (1999), *B-ISDN operation and maintenance principles and functions*.
+
+- [11] ITU-T Recommendation Q.922 (1992), *ISDN data link layer specification for frame mode bearer services*.
+- [12] ETSI TS 126 071 V3.0.1 (2000-02), *Universal Mobile Telecommunications System (UMTS); AMR Speech Codec; General description*.
+- [13] IETF RFC 3031 (2001), *Multiprotocol Label Switching Architecture*.
+- [14] IETF RFC 3032 (2001), *MPLS Label Stack encoding*.
+- [15] IETF RFC 3036 (2001), *LDP Specification*.
+- [16] IETF RFC 3270 (2002) *Multi-Protocol Label Switching (MPLS). Support of Differentiated Services*.
+
+## 2.2 Informative references
+
+- [17] ITU-T Recommendation Q.1950 (2002), *Bearer independent call bearer control protocol*.
+- [18] IETF RFC (1996), *RTP: A Transport Protocol For Real-Time applications*.
+- [19] IETF RFC 1890 (1996), *RTP Profile for Audio and Video Conferences with Minimal Control*.
+- [20] FRF.11.1 (1999), *Voice over Frame Relay Implementation Agreement*.
+- [21] MPLS Forum 1.0 (2001), *Voice over MPLS – Bearer Transport Implementation Agreement*.
+
+# 3 Definitions
+
+This Recommendation defines the following terms:
+
+**3.1 voice services over MPLS:** The term encompasses the set of technical approaches used to transport encoded voice over MPLS. This terminology is independent of the method by which MPLS frames are transported.
+
+**3.2 active voice:** A sampled audio interval that has been determined to contain speech as opposed to silence. The classification is made by a Voice Activity Detection algorithm. It enables discontinuous transmission, whereby the bit rate of the signal is reduced during silent intervals.
+
+**3.3 audio:** In the context of this Recommendation, audio is used as a general term for signals of the audible medium, including voice and voiceband data.
+
+**3.4 channel-associated signalling:** Bits dedicated for connection control across a 1544 kbit/s or 2048 kbit/s interface that carries 64 kbit/s channels. Procedures are based on the state of up to four signalling bits (A, B, C, D) that are allocated per channel per multiframe.
+
+**3.5 circuit mode data:** A continuous stream of digital information at 64 kbit/s or  $2 \times 64$  kbit/s having an 8 kHz structure.
+
+**3.6 dialled digits:** Multifrequency audio tones typically used for inter-register signalling of addresses during call set-up or for end-to-end device control during an established call. Depending on the system, codes are defined for the digits 0-9 of a telephone keypad and other auxiliary signals.
+
+**3.7 facsimile demodulation/remodulation:** The process of detecting facsimile traffic, extracting digital information from the incoming analogue modulated signal, transporting this across a trunk in packet formats, and reproducing the facsimile control and image information by remodulation at the other end.
+
+**3.8 silence insertion descriptor:** A compressed representation of the audio background noise that can be sent during silent intervals. SIDs may not be continuous and may only be sent when
+
+there is a change in noise characteristics. Playing out received SIDs is known as Comfort Noise Generation.
+
+# **4 Abbreviations**
+
+This Recommendation uses the following abbreviations:
+
+|      |                                       |
+|------|---------------------------------------|
+| AAL  | ATM Adaptation Layer                  |
+| AMR  | Adaptive Multi-Rate                   |
+| ATM  | Asynchronous Transfer Mode            |
+| BICC | Bearer Independent Call Control       |
+| CAS  | Channel-Associated Signalling         |
+| CPCS | Common Part Convergence Sublayer      |
+| DTMF | Dual-Tone Multi-Frequency             |
+| GW   | Gateway                               |
+| IP   | Internet Protocol                     |
+| ISDN | Integrated Services Digital Network   |
+| LER  | Label Edge Router                     |
+| LSP  | Label Switched Path                   |
+| LSR  | Label Switching Router                |
+| MG   | Media Gateway                         |
+| MGC  | Media Gateway Controller              |
+| MPLS | Multi-Protocol Label Switching        |
+| MSC  | Mobile Switching Center               |
+| MTU  | Maximum Transmission Unit             |
+| NT   | Network Termination                   |
+| PSTN | Public Switched Telephone Network     |
+| RAN  | Radio Access Network                  |
+| RTP  | Real-Time Transport Protocol          |
+| SSCS | Service-Specific Convergence Sublayer |
+| TDM  | Time Division Multiplexing            |
+| UDP  | User Datagram Protocol                |
+
+# **5 Architecture**
+
+MPLS is being introduced into IP networks to support Traffic Engineering and various applications. One of the motivations for Voice Services over MPLS is to take advantage of the MPLS network capabilities to improve voice services by:
+
+- using label-switched-paths as a bearer capability for encoded voice thereby providing appropriate QoS capability;
+- providing efficient transport mechanism.
+
+## 5.1 Voice Services over MPLS logical service reference model
+
+A logical service reference model for Voice Services over MPLS consists of two main components:
+
+- 1) a high-capacity MPLS core network consisting of MPLS nodes (LSR) with support of MPLS control protocols;
+- 2) Gateway Devices used at the edge of the MPLS network to perform interworking between a variety of technologies such as ATM, frame relay, TDM, IP, PSTN, ISDN, etc. and the MPLS network.
+
+Figure 1 shows the Voice Services over MPLS logical service reference model including control plane, transport plane, and management plane.
+
+![Figure 1: Voice Services over MPLS logical service reference model. The diagram is divided into two main sections: 'Logical view' (top) and 'Physical network' (bottom), separated by a dashed line. In the 'Logical view', three planes are shown: 'Management plane', 'User plane', and 'Control plane'. Each plane is connected to a 'GW' (Gateway device) on the left and a 'GW' on the right. These GWs are connected to three corresponding networks: 'Management network', 'Transport network', and 'Signalling network'. In the 'Physical network' section, the left and right GWs are connected to physical networks labeled 'e.g. PSTN, ISDN, ATM'. The central 'MPLS network' is shown as a core network with 'Label Edge Router' (LER) nodes at the edges and 'Label Switching Router' (LSR) nodes in the center. A 'Label Switched Path' (LSP) is highlighted with a red line connecting the LERs through the LSRs. A legend at the bottom left defines the symbols: GW (Gateway device), Link (dashed line), LER (Label Edge Router, represented by a circle), LSP (Label Switched Path, represented by a red line), and LSR (Label Switching Router, represented by a blue dot). The identifier 'Y.1261_F01' is located at the bottom right of the diagram area.](daa4a6fa7e2ba1954258f86b4928eb32_img.jpg)
+
+GW Gateway device
+
+----- Link
+
+○ Label Edge Router
+
+— Label Switched Path
+
+● Label Switching Router
+
+Y.1261\_F01
+
+Figure 1: Voice Services over MPLS logical service reference model. The diagram is divided into two main sections: 'Logical view' (top) and 'Physical network' (bottom), separated by a dashed line. In the 'Logical view', three planes are shown: 'Management plane', 'User plane', and 'Control plane'. Each plane is connected to a 'GW' (Gateway device) on the left and a 'GW' on the right. These GWs are connected to three corresponding networks: 'Management network', 'Transport network', and 'Signalling network'. In the 'Physical network' section, the left and right GWs are connected to physical networks labeled 'e.g. PSTN, ISDN, ATM'. The central 'MPLS network' is shown as a core network with 'Label Edge Router' (LER) nodes at the edges and 'Label Switching Router' (LSR) nodes in the center. A 'Label Switched Path' (LSP) is highlighted with a red line connecting the LERs through the LSRs. A legend at the bottom left defines the symbols: GW (Gateway device), Link (dashed line), LER (Label Edge Router, represented by a circle), LSP (Label Switched Path, represented by a red line), and LSR (Label Switching Router, represented by a blue dot). The identifier 'Y.1261\_F01' is located at the bottom right of the diagram area.
+
+**Figure 1/Y.1261 – Voice Services over MPLS logical service reference model**
+
+## 5.2 Voice services over MPLS Reference Architecture
+
+Figure 2 identifies the Reference Architecture for Voice Services over MPLS. The MPLS network contains a number of Gateway devices (GW), Label Switching Routers (LSR), and Label Switched Paths (LSP) [13], [14], [15]. An example LSP is shown as a solid line in the figure. Gateways may be directly connected to each other or indirectly connected through a number of LSRs.
+
+![Figure 2/Y.1261 – Voice services over MPLS Reference Architecture diagram](e9314c83043183351ed74908e9bf2f90_img.jpg)
+
+The diagram illustrates the Reference Architecture for Voice Services over MPLS. It shows a central MPLS network (cloud shape) connected to two external networks (cloud shapes) labeled "PSTN, ISDN, ATM". The MPLS network contains three Gateway devices (GW) and four Label Switching Routers (LSR). The GWs are labeled "GW IWF" and are connected to the LSRs. A "Voice terminal" is connected to the top GW. A "Label Switched Path" (LSP) is shown as a solid green line connecting the left GW to the right GW through the LSRs. Physical links are shown as dashed lines. A legend at the bottom left defines the symbols: GW (Gateway device), IWF (Interworking Function), LSP (Label Switched Path), Physical link (dashed line), and LSR (Label Switching Router). The text "Y.1261\_F02" is located at the bottom right of the diagram.
+
+Figure 2/Y.1261 – Voice services over MPLS Reference Architecture diagram
+
+**Figure 2/Y.1261 – Voice services over MPLS Reference Architecture**
+
+Gateway devices include LER functionality as well as the interworking functions.
+
+This architecture should be capable of supporting different LSP configurations (e.g., E-LSP, L-LSP [16], hierarchical LSP, etc.) to convey voice payloads in an MPLS environment.
+
+NOTE – Voice Services over MPLS can be deployed in both core and access networks. Network architecture functions and definitions for the usage of Voice Services over MPLS in access networks are for further study.
+
+# 6 Requirements for Voice Services over MPLS
+
+The following subclauses provide a list of requirements for Voice Services over MPLS. The relative priority of these requirements is Service Provider specific.
+
+## 6.1 General service requirements
+
+The following provides a list of general service requirements:
+
+- 1) The architecture should be capable of supporting carrier-grade networks (e.g., support of a large number of voice calls as well as a rapid rate of voice call requests, etc.) in accordance with existing Recommendations for voice networks.
+- 2) If a solution makes use of mechanisms which apply only in restricted environments, a clear statement about the restricted applicability must be included.
+- 3) Multiple applications may be supported (e.g., facsimile, video, etc.)
+
+Table 1 below summarises the categories and the corresponding delivered services which have been identified in the "Voice Services over MPLS" family.
+
+**Table 1/Y.1261 – Categories for Voice Services over MPLS**
+
+| Category                                                                      | Services delivered                                          |
+|-------------------------------------------------------------------------------|-------------------------------------------------------------|
+| Audio                                                                         | Digitized Voice                                             |
+|                                                                               | Alarm                                                       |
+|                                                                               | Silence information descriptor                              |
+|                                                                               | Dialled digits                                              |
+|                                                                               | Channel-associated signalling                               |
+|                                                                               | Facsimile – voiceband data                                  |
+|                                                                               | Facsimile remodulation/demodulation                         |
+|                                                                               | Circuit mode data for 64 kbit/s or $2 \times 64$ kbit/s     |
+| Multirate                                                                     | Circuit mode data for $N \times 64$ kbit/s, $2 < N \leq 31$ |
+|                                                                               | Alarm                                                       |
+| Video                                                                         | Video                                                       |
+|                                                                               | Alarm                                                       |
+| NOTE – Either one category or any combination of categories may be supported. |                                                             |
+
+## 6.2 User plane requirements
+
+The following provides a list of requirements for the user plane:
+
+- 1) Multiplexing encoded voice samples from different calls into a single MPLS frame should be supported.
+- 2) The bandwidth should not be used by the voice application when it is not needed – when the talk is silent or when the call is completed.
+- 3) The user plane protocol should be efficient in terms of bandwidth.
+- 4) The capability to implement echo cancellation functionality to reduce echo should be supported.
+- 5) QoS/SLA (jitter, loss, bandwidth, delay) commitments for the voice service must be supported.
+- 6) Uncompressed (i.e., G.711 64 kbit/s, both A-law and  $\mu$ -law) and compressed voice (G.726 16/24/32/40 kbit/s, G.729 8 kbit/s, G.723.1 5.3/6.3 kbit/s) should be supported ([1], [2], [3], [4]).
+- 7) Standard encoding schemes should be supported.
+- 8) Specific families of related encoding algorithms (e.g., AMR [12]) should experience minimum disruption in audio when the algorithm rate is changed during the call.
+- 9) Silence suppression, i.e., non-transfer of MPLS subframes during silent intervals should be supported. Generic Silence Insertion Descriptor for voice encodings that do not contain this capability should be supported.
+- 10) DTMF transport should be supported.
+- 11) Voiceband data through modem detection should be supported.
+- 12) Transport of Channel-Associated Signalling bits should be supported.
+
+## 6.3 User plane requirements for combined audio and video service
+
+The following provides a list of user plane requirements for the combined audio and video service:
+
+- 1) Multimedia applications may be supported.
+
+- 2) If multimedia applications are supported, standard video schemes should be supported (e.g., CelB, JPEG, H261, MPV, MP2T, and H263).
+- 3) One video call may be mapped to one LSP. Mapping more than one video call to single LSP is for further study.
+- 4) Higher resolution timer (e.g., 90 kHz for IP video) and indication of end of frame should be supported.
+- 5) Variable length and large payloads up to MTU size minus the MPLS overhead of the underlying link layer for MPLS should be supported.
+
+## **6.4 Control plane requirements**
+
+The following provides a list of requirements for the control plane:
+
+- 1) LSPs that are used for Voice Services over MPLS may be either established on demand or via management procedures.
+- 2) Voice call channel parameters (e.g., bandwidth, QoS, etc.) applicable to both single and multiplexed channels in an LSP may be either statically or dynamically provisioned.
+
+## **6.5 Management plane requirements**
+
+The management plane should provide the following functions:
+
+- a) Resource management (e.g., bandwidth, label, addresses, etc.)
+- b) Parameter management (e.g., priority of traffic, sampling and framing period of voice)
+- c) Monitoring and maintenance:
+  - connection identification;
+  - connection state monitoring;
+  - fault detection and notification;
+  - alarm capabilities.
+
+# **7 Voice Services over MPLS interworking requirements**
+
+## **7.1 Voice Services over MPLS Interworking requirements with Voice over IP**
+
+- 1) ITU-T Rec. G.711 must be supported without negotiation.
+- 2) Video and combined audio and video services may be supported.
+- 3) Tones and DTMF digits should be supported.
+
+## **7.2 Voice Services over MPLS interworking requirements with Voice over ATM**
+
+- 1) Narrowband services defined in ITU-T Rec. I.366.2 should be supported.
+- 2) Interworking of operation and maintenance capabilities defined in ITU-T Rec. I.610 [10] should be supported.
+- 3) Mapping of ATM traffic and QoS parameters to MPLS LSPs should be supported.
+
+## **7.3 Voice Services over MPLS interworking requirements with Voice over Frame Relay**
+
+Support is for further study.
+
+## **7.4 Voice Services over MPLS interworking requirements with PSTN/ISDN**
+
+- 1) Interworking with PSTN/ISDN should be supported.
+
+## **7.5 Voice Services over MPLS Interworking requirements with mobile access networks**
+
+Support is for further study.
+
+# **Appendix I**
+
+## **Voice over Packet Protocol architectures**
+
+In recent years, voice over packet protocols were developed for different packet networks. They include: Voice over Frame Relay, Voice over ATM using AAL type2 as described in ITU-T Rec. I.366.2 [9] and Voice over Internet Protocol. Each of these packet voice schemes developed a transport protocol for providing end-to-end network transport for voice applications.
+
+These Voice over Packet protocols provide functionalities similar to Voice Services over MPLS in the User plane protocol.
+
+### **I.1 Voice over Frame Relay**
+
+The Frame Relay Forum developed the Voice over Frame Relay implementation agreement [20]. Transport of uncompressed and compressed voice is provided with a generalized frame format that supports multiplexing of subchannels on a single frame relay connection. Support for the unique needs of the different voice compression algorithms is accommodated with algorithm-specific "transfer syntax" definitions. These definitions establish algorithm specific frame formats and procedures.
+
+Transport of supporting information for voice communication, such as signalling indications (e.g., ABCD bits), dialled digits, and facsimile data, is also provided through the use of transfer syntax definitions specific to the information being sent.
+
+#### **I.1.1 FR reference model and service description**
+
+In the FR reference model (Figure I.1), a Voice Frame Relay Access Device can exchange voice information over a FR connection with another Voice Frame Relay Access Device. It could also use the Voice over Frame Relay protocol stack on a connection to a transparent channel bank into a private network (middle right) or to a PBX (bottom right).
+
+A block diagram for the Voice over Frame Relay service is provided in Figure I.2 and identifies the information provided to users of the Voice over Frame Relay service.
+
+![Figure I.1/Y.1261 – Voice over Frame Relay network reference model. This diagram shows a central cloud labeled 'Frame Relay' connected to six nodes. Each node represents a different network element: 1. Application (e.g., Fax) with a VoFR stack. 2. Transparent (e.g., Channel bank) with a Voice interface and a VoFR stack. 3. Switching (e.g., PBX) with a Voice interface and a VoFR stack. 4. Application (e.g., Fax) with a VoFR stack. 5. Transparent (e.g., Channel bank) with a VoFR stack and a Voice interface. 6. Switching (e.g., PBX) with a VoFR stack and a Voice interface. The connections show the flow of data through the Frame Relay network.](33ed1f9b27c7c21c797aa928b0f06851_img.jpg)
+
+Y.1261\_Fl.1
+
+Figure I.1/Y.1261 – Voice over Frame Relay network reference model. This diagram shows a central cloud labeled 'Frame Relay' connected to six nodes. Each node represents a different network element: 1. Application (e.g., Fax) with a VoFR stack. 2. Transparent (e.g., Channel bank) with a Voice interface and a VoFR stack. 3. Switching (e.g., PBX) with a Voice interface and a VoFR stack. 4. Application (e.g., Fax) with a VoFR stack. 5. Transparent (e.g., Channel bank) with a VoFR stack and a Voice interface. 6. Switching (e.g., PBX) with a VoFR stack and a Voice interface. The connections show the flow of data through the Frame Relay network.
+
+**Figure I.1/Y.1261 – Voice over Frame Relay network reference model**
+
+![Figure I.2/Y.1261 – Voice over Frame Relay service block diagram. This block diagram illustrates the service flow. At the top is the 'Voice over Frame Relay service user'. Below it is the 'Voice over Frame Relay service' block, which contains two sub-blocks: 'Primary payloads' and 'Signalled payloads'. Between the user and the service block, there are eight vertical double-headed arrows representing data flows: 'Voice', 'Delay', 'Encoded Fax', 'Fault indication', 'Dialled digits', 'Encoded Fax', 'Signalling bits (CAS)', and 'Silence information'. At the bottom is the 'Frame Relay service' block. A single vertical double-headed arrow labeled 'Service Data Units' connects the 'Voice over Frame Relay service' block to the 'Frame Relay service' block.](724c7777b608e53be38b12b6fb3c43bc_img.jpg)
+
+Y.1261\_Fl.2
+
+Figure I.2/Y.1261 – Voice over Frame Relay service block diagram. This block diagram illustrates the service flow. At the top is the 'Voice over Frame Relay service user'. Below it is the 'Voice over Frame Relay service' block, which contains two sub-blocks: 'Primary payloads' and 'Signalled payloads'. Between the user and the service block, there are eight vertical double-headed arrows representing data flows: 'Voice', 'Delay', 'Encoded Fax', 'Fault indication', 'Dialled digits', 'Encoded Fax', 'Signalling bits (CAS)', and 'Silence information'. At the bottom is the 'Frame Relay service' block. A single vertical double-headed arrow labeled 'Service Data Units' connects the 'Voice over Frame Relay service' block to the 'Frame Relay service' block.
+
+**Figure I.2/Y.1261 – Voice over Frame Relay service block diagram**
+
+#### I.1.2 Multiplexing
+
+The Voice over Frame Relay service supports multiple voice and data channels on a single frame relay data link connection. The Voice over Frame Relay service delivers frames on each sub-channel in the order they were sent.
+
+Voice and data payloads are multiplexed within a voice over frame relay data link connection by encapsulation within the FR frame. Each payload is packaged as a sub-frame within a frame's information field. Sub-frames may be combined within a single frame to increase processing and
+
+transport efficiencies. Each sub-frame contains a header and payload. The sub-frame header identifies the voice/data sub-channel and, when required, payload type and length.
+
+#### I.1.3 Voice over Frame Relay user plane protocol stack
+
+In the case of Voice over Frame Relay, the user plane protocol stack consists of: *Physical layer/Q.922 Annex A/Voice over Frame Relay* as shown in Figure I.3 [11]. The higher layer (i.e., Voice over Frame Relay) is providing the voice protocol. The Voice over Frame Relay protocol is the User plane protocol in this case and provides peer-to-peer layer communications in a Frame Relay network.
+
+![](1a827b10290f33d4fec04d0e8ef7a897_img.jpg)
+
+|                        |
+|------------------------|
+| Voice                  |
+| Voice over Frame relay |
+| Q.922 Annex A          |
+| Physical layer         |
+
+**Figure I.3/Y.1261 – Voice over Frame Relay protocol stack**
+
+### I.2 Voice over ATM as described in AAL type 2 Service Specific Convergence Sublayer for trunking [9]
+
+Figure I.4 shows an example of narrow-band trunking supported in AAL type 2 Service Specific Convergence Sublayer for trunking [9].
+
+The Service-Specific Convergence Sublayer (SSCS) carries the information content of one narrow-band call over each AAL type 2 connection – with the appropriate bearer capability. Secondary messaging, such as frame mode data, dialled digits, channel-associated signalling bits, and alarms may be interleaved on the same AAL type 2 connection.
+
+![Diagram illustrating the deployment example of narrow-band trunking. It shows two PBXs connected to a central B-ISDN network via Trunk interfaces. The left side shows a TDM/ATM interface, and the right side shows an ATM/TDM interface. The B-ISDN network is represented by a central oval with two lines connecting to the Trunk interfaces on both sides.](b90144cfbb81a2d610d920240fda689d_img.jpg)
+
+The diagram illustrates a narrow-band trunking deployment. On the left, two PBX (Private Branch Exchange) boxes are connected to a central 'Trunk interface' box. A vertical dashed line separates the 'TDM' side from the 'ATM' side. The 'Trunk interface' box is connected to a central oval labeled 'B-ISDN'. On the right, the 'B-ISDN' oval is connected to another 'Trunk interface' box, which is then connected to two more PBX boxes. A vertical dashed line separates the 'ATM' side from the 'TDM' side. The label 'Y.1261\_FI.4' is located at the bottom right of the diagram.
+
+Diagram illustrating the deployment example of narrow-band trunking. It shows two PBXs connected to a central B-ISDN network via Trunk interfaces. The left side shows a TDM/ATM interface, and the right side shows an ATM/TDM interface. The B-ISDN network is represented by a central oval with two lines connecting to the Trunk interfaces on both sides.
+
+**Figure I.4/Y.1261 – Deployment example of narrow-band trunking**
+
+At each end of a trunk, the User coordinates the operations of the SSCS. The services offered by the SSCS are delivered through Service Access Points (SAPs).
+
+The audio, circuit mode data, and facsimile demodulation/remodulation services represent primary information streams of the audio service. Only one of these streams can be transported on an AAL type 2 connection at a given time.
+
+The dialled digits service is a secondary information stream. It could be transported simultaneously with one of the primary streams, but it is anticipated that the primary stream will be made idle during the transport of dialled digits. The frame mode data, channel-associated signalling, and
+
+alarms services are secondary information streams that can be transported simultaneously with one of the primary information streams.
+
+#### **I.2.1 User plane protocol stack for Voice over ATM as described in AAL type 2 Service-Specific Convergence Sublayer for trunking [9]**
+
+For voice over ATM using AAL Type 2 as described in ITU-T Rec. I.366.2, the user plane protocol stack consists of: *physical layer/ATM layer/ (AAL 2 common part + AAL 2 service specific part)/Voice*.
+
+The service-specific part of AAL sublayer performs different functions depending on the service. I.366.2 defines how to transport audio service information between trunking interfaces.
+
+|                                          |
+|------------------------------------------|
+| Voice                                    |
+| AAL 2 Service-Specific Part<br>(I.366.2) |
+| AAL 2 Common Part<br>(I.366.2)           |
+| ATM                                      |
+| Physical Layer                           |
+
+**Figure I.5/Y.1261 – User plane protocol stack for Voice over ATM as described in AAL type 2 Service-Specific Convergence Sublayer for trunking [9]**
+
+### **I.3 Voice over IP**
+
+The user plane protocol for a Voice over IP stack is shown in Figure I.6.
+
+|                |
+|----------------|
+| Voice          |
+| RTP            |
+| UDP            |
+| IP             |
+| Link Layer     |
+| Physical Layer |
+
+**Figure I.6/Y.1261 – Voice over IP protocol stack**
+
+The RTP protocol provides end-to-end network transport functions suitable for audio application. Those functions include payload type identification, sequence numbering, and time stamping.
+
+RTP provides the information required by a particular application and will often be integrated into the application processing rather than being implemented as a separate layer. RTP along with application profiles for audio provides the transport services for voice application. The profile specifications define a set of payload type codes and their mapping to payload formats.
+
+The RTP header contains timing information and a sequence number that allows the receiver to reconstruct the sample produced by the source.
+
+# Appendix II
+
+## Alternate solutions for Voice Services over MPLS
+
+MPLS provides a link layer independent transport framework and uses existing IP mechanisms for addressing and routing of traffic. There are several possibilities to provide Voice Services over MPLS.
+
+It is important to realize that MPLS networks will evolve from existing networks; existing services and capabilities will have to be supported and interwork with the MPLS networks.
+
+![Diagram illustrating alternate solutions for Voice Services over MPLS. The diagram shows a central MPLS network (Transport Network) connected to two external networks (e.g., PSTN, ISDN, ATM). The MPLS network supports various voice services: Voice Services over MPLS solutions (Voice over MPLS, MPLS Forum IA 1.0, AAL 1, AAL 2, AAL 5), I.366.2 Trunking format, Voice over IP (RTP/UDP/IP), and Voice over ATM (AAL 1, AAL 2, AAL 5).](9b9d2abd741ed4bafe7f78f89961c663_img.jpg)
+
+The diagram illustrates the architecture for voice services over MPLS. It features a central 'Transport Network' (MPLS) flanked by two external networks, each labeled 'e.g., PSTN, ISDN, ATM (existing services and capabilities)'. The MPLS network is shown as a vertical bar with a dashed line indicating its internal structure. The external networks are represented by large ovals. The MPLS network supports several voice services, which are listed in the center: 'Voice Services over MPLS solutions' (including 'Voice over MPLS', 'MPLS Forum IA 1.0', and 'AAL 1, AAL 2, AAL 5'), 'I.366.2 Trunking format', 'Voice over IP (RTP/UDP/IP)', and 'Voice over ATM (AAL 1, AAL 2, AAL 5)'. The MPLS network is also labeled 'MPLS' at the bottom. The entire diagram is labeled 'Y1261\_FII.1' in the bottom right corner.
+
+Diagram illustrating alternate solutions for Voice Services over MPLS. The diagram shows a central MPLS network (Transport Network) connected to two external networks (e.g., PSTN, ISDN, ATM). The MPLS network supports various voice services: Voice Services over MPLS solutions (Voice over MPLS, MPLS Forum IA 1.0, AAL 1, AAL 2, AAL 5), I.366.2 Trunking format, Voice over IP (RTP/UDP/IP), and Voice over ATM (AAL 1, AAL 2, AAL 5).
+
+**Figure II.1/Y.1261 – Alternate solutions for Voice Services over MPLS**
+
+### II.1 Voice over ATM
+
+The coded voice over an ATM connection [5] can be transported using:
+
+- a) Voice over AAL 1;
+- b) Voice over AAL 2;
+- c) Voice over AAL 5.
+
+This approach uses respectively ATM AAL type 1 [6], AAL type 2 [7] [9], or AAL type 5 [8].
+
+Using this approach over an MPLS network, ATM/MPLS network interworking or AAL/MPLS network interworking can be used. ATM cells or AAL frames are received at the ATM/MPLS network gateway.
+
+NOTE – ATM/MPLS and AAL/MPLS interworking specifications are currently under development.
+
+|                         |
+|-------------------------|
+| Voice                   |
+| AAL 1 or AAL 2 or AAL 5 |
+| ATM                     |
+| MPLS                    |
+| Link layer              |
+| Physical layer          |
+
+**Figure II.2/Y.1261 – Voice over ATM protocol stack**
+
+### **II.2 Voice over IP**
+
+MPLS will be used to transport IP frames. Voice over IP is transparent to MPLS. RFC 1889 [18], and RFC 1890 [15] are used by this approach.
+
+|                |
+|----------------|
+| Voice          |
+| RTP            |
+| UDP            |
+| IP             |
+| MPLS           |
+| Link layer     |
+| Physical layer |
+
+**Figure II.3/Y.1261 – Voice over IP protocol stack**
+
+### **II.3 I.366.2 Voice Trunking format over MPLS**
+
+This approach describes a mechanism using the same format of AAL type 2 CPCS packet encapsulated within MPLS frames. It uses variable length packets with are formatted as described in ITU-T Rec. I.366.2, but carried by MPLS frames and not ATM cells.
+
+In this approach, the segmentation and reassembly (SAR) functionality as well as the start field are not required. Similarly, the AAL-CU timer and related functionality are not required.
+
+|                                   |
+|-----------------------------------|
+| Voice                             |
+| I.366.2 Trunking format over MPLS |
+| MPLS                              |
+| Link layer                        |
+| Physical layer                    |
+
+**Figure II.4/Y.1261 – I.366.2 Voice Trunking format over MPLS protocol stack**
+
+### **II.4 Voice over MPLS**
+
+This approach is based on the MPLS Forum Implementation Agreement 1.0 [21]. In this case, the protocol stack consists of voice samples directly encapsulated in the MPLS frame.
+
+|                                      |
+|--------------------------------------|
+| Voice                                |
+| Voice over MPLS<br>MPLS Forum IA 1.0 |
+| MPLS                                 |
+| Link layer                           |
+| Physical layer                       |
+
+**Figure II.5/Y.1261 – Voice over MPLS protocol stack**
+
+### **II.5 Summary of different solutions for Voice Services over MPLS**
+
+Figure II.6 summarizes a number of protocol stacks to support Voice Services over MPLS (those described in Appendix II).
+
+|                                      |                                            |     |                    |                             |  |  |
+|--------------------------------------|--------------------------------------------|-----|--------------------|-----------------------------|--|--|
+| Voice                                |                                            |     |                    |                             |  |  |
+|                                      |                                            | RTP |                    |                             |  |  |
+|                                      |                                            | UDP | AAL 1<br>(I.363.1) | AAL 2<br>(I.363.2, I.366.2) |  |  |
+| Voice over MPLS<br>MPLS Forum IA 1.0 | I.366.2 Voice trunking<br>format over MPLS | IP  | ATM                |                             |  |  |
+| MPLS layer                           |                                            |     |                    |                             |  |  |
+| Link layer                           |                                            |     |                    |                             |  |  |
+| Physical layer                       |                                            |     |                    |                             |  |  |
+
+**Figure II.6/Y.1261 – Various protocol stacks for support of Voice Services over MPLS**
+
+# **Appendix III**
+
+## **BICC architecture**
+
+An instance of the Bearer Independent Call Control (BICC) architecture is shown in Figure III.1 [17]. It consists of ATM or IP backbone networks and Media gateways (MG) connected to network edge nodes. The role of a MG is to map TDM time slots to ATM cells or IP packets and vice versa. MGs can be either line (local loop) or trunk MGs. Media gateway controllers (MGC) perform call control functions and interact with one or more MGs under their control.
+
+![Diagram of BICC architecture showing two symmetrical paths. Each path starts with a CPE connected to an EO (End Office), which connects to a TO (Trunk Office). The TO connects to an MG (Media Gateway), which then connects to an MGC (Media Gateway Controller). The MGCs are connected via a Signalling network. The MGs connect to Network edge nodes, which interface with an ATM or IP network. The Network edge nodes connect to another MG, which then connects to another TO, EO, and CPE. A legend defines CPE as Customer Premises Equipment, EO as End Office, and TO as Trunk Office. The reference Y.1261_FIII.1 is noted at the bottom right.](5b8a756d9a71c35f17db8bcb90b438a3_img.jpg)
+
+Y.1261\_FIII.1
+
+CPE    Customer Premises Equipment  
+ EO    End Office  
+ TO    Trunk Office
+
+Diagram of BICC architecture showing two symmetrical paths. Each path starts with a CPE connected to an EO (End Office), which connects to a TO (Trunk Office). The TO connects to an MG (Media Gateway), which then connects to an MGC (Media Gateway Controller). The MGCs are connected via a Signalling network. The MGs connect to Network edge nodes, which interface with an ATM or IP network. The Network edge nodes connect to another MG, which then connects to another TO, EO, and CPE. A legend defines CPE as Customer Premises Equipment, EO as End Office, and TO as Trunk Office. The reference Y.1261\_FIII.1 is noted at the bottom right.
+
+**Figure III.1/Y.1261 – An instance of BICC architecture**
+
+When MGs are connected to an ATM network, AAL type 1 or AAL type 2 may be used to transport voice services. When MGs are connected to an IP network, RTP over UDP and IP is used. MGs interface to the PSTN with TDM 64 kbit/s channels.
+
+So far BICC supports ATM networks with AAL type 1 and type 2 and IP networks with RTP/UDP/IP for voice transport.
+
+Current BICC capabilities will remain for some time when the network evolves to the multi-service MPLS network.
+
+Detailed BICC architecture and its evolution for MPLS network control is out of scope of this Recommendation.
+
+# Appendix IV
+
+## Examples of Voice Services over MPLS deployment scenarios
+
+LSPs that are used for Voice Services over MPLS could be either established on demand or via management procedures. Depending on the specific application, the mapping of voice call information streams (e.g., time slots on a primary rate interface) to multiplexed streams could be either static or dynamic. Voice calls could even be switched at an external interface to one of several outgoing LSPs, based on an analysis of the destination address.
+
+These are possible applications of Voice Services over MPLS and are provided just as deployment examples.
+
+![Figure IV.1/Y.1261: Deployment example of Voice Services over MPLS for trunking. The diagram shows a TDM network on the left connected to a 'Trunk interface' box. This box is connected to an 'MPLS' cloud. The 'MPLS' cloud is connected to two 'Trunk interface' boxes on the right, which are then connected to two separate 'TDM' networks.](e69b9188aa2c14ec6b21c83f711fef65_img.jpg)
+
+Y.1261\_FIV.1
+
+Figure IV.1/Y.1261: Deployment example of Voice Services over MPLS for trunking. The diagram shows a TDM network on the left connected to a 'Trunk interface' box. This box is connected to an 'MPLS' cloud. The 'MPLS' cloud is connected to two 'Trunk interface' boxes on the right, which are then connected to two separate 'TDM' networks.
+
+**Figure IV.1/Y.1261 – Deployment example of Voice Services over MPLS for trunking**
+
+![Figure IV.2/Y.1261: Deployment example of Voice Services over MPLS for trunking, for mobile access, and for fixed line access. The diagram shows a TDM network on the left connected to a 'Local exchange' box. This box is connected to an 'MPLS' cloud. The 'MPLS' cloud is connected to three components on the right: an 'MSC' box, an 'NT' box, and a 'Trunk interface' box. The 'MSC' box is connected to a 'RAN' network, and the 'Trunk interface' box is connected to a 'TDM' network.](d53cd0fd1cf896a9353fd63de1505ba2_img.jpg)
+
+Y.1261\_FIV.2
+
+Figure IV.2/Y.1261: Deployment example of Voice Services over MPLS for trunking, for mobile access, and for fixed line access. The diagram shows a TDM network on the left connected to a 'Local exchange' box. This box is connected to an 'MPLS' cloud. The 'MPLS' cloud is connected to three components on the right: an 'MSC' box, an 'NT' box, and a 'Trunk interface' box. The 'MSC' box is connected to a 'RAN' network, and the 'Trunk interface' box is connected to a 'TDM' network.
+
+**Figure IV.2/Y.1261 – Deployment example of Voice Services over MPLS for trunking, for mobile access, and for fixed line access**
+
+
+
+# SERIES OF ITU-T RECOMMENDATIONS
+
+|                 |                                                                                                                                |
+|-----------------|--------------------------------------------------------------------------------------------------------------------------------|
+| Series A        | Organization of the work of ITU-T                                                                                              |
+| Series B        | Means of expression: definitions, symbols, classification                                                                      |
+| Series C        | General telecommunication statistics                                                                                           |
+| Series D        | General tariff principles                                                                                                      |
+| Series E        | Overall network operation, telephone service, service operation and human factors                                              |
+| Series F        | Non-telephone telecommunication services                                                                                       |
+| Series G        | Transmission systems and media, digital systems and networks                                                                   |
+| Series H        | Audiovisual and multimedia systems                                                                                             |
+| Series I        | Integrated services digital network                                                                                            |
+| Series J        | Cable networks and transmission of television, sound programme and other multimedia signals                                    |
+| Series K        | Protection against interference                                                                                                |
+| Series L        | Construction, installation and protection of cables and other elements of outside plant                                        |
+| Series M        | TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits |
+| Series N        | Maintenance: international sound programme and television transmission circuits                                                |
+| Series O        | Specifications of measuring equipment                                                                                          |
+| Series P        | Telephone transmission quality, telephone installations, local line networks                                                   |
+| Series Q        | Switching and signalling                                                                                                       |
+| Series R        | Telegraph transmission                                                                                                         |
+| Series S        | Telegraph services terminal equipment                                                                                          |
+| Series T        | Terminals for telematic services                                                                                               |
+| Series U        | Telegraph switching                                                                                                            |
+| Series V        | Data communication over the telephone network                                                                                  |
+| Series X        | Data networks and open system communications                                                                                   |
+| <b>Series Y</b> | <b>Global information infrastructure and Internet protocol aspects</b>                                                         |
+| Series Z        | Languages and general software aspects for telecommunication systems                                                           |
+
+![Barcode with numbers 2 3 4 5 7 and asterisks](05c9994c1f5daf53d0d9b107657d7a17_img.jpg)
+
+A standard 1D barcode is located at the bottom right of the page. Below the vertical bars, the numbers 2, 3, 4, 5, and 7 are printed, flanked by asterisks on both sides: \* 2 3 4 5 7 \*.
+
+Barcode with numbers 2 3 4 5 7 and asterisks

marked/Y/T-REC-Y.1271-201407-I_PDF-E/raw.md

@@ -0,0 +1,666 @@
+
+
+# ITU-T
+
+TELECOMMUNICATION  
+STANDARDIZATION SECTOR  
+OF ITU
+
+## Y.1271
+
+(07/2014)
+
+SERIES Y: GLOBAL INFORMATION  
+INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS  
+AND NEXT-GENERATION NETWORKS
+
+Internet protocol aspects – Architecture, access, network  
+capabilities and resource management
+
+---
+
+**Framework(s) on network requirements and  
+capabilities to support emergency  
+telecommunications over evolving circuit-  
+switched and packet-switched networks**
+
+Recommendation ITU-T Y.1271
+
+# ITU-T Y-SERIES RECOMMENDATIONS
+
+# GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS
+
+## GLOBAL INFORMATION INFRASTRUCTURE
+
+|                                           |             |
+|-------------------------------------------|-------------|
+| General                                   | Y.100–Y.199 |
+| Services, applications and middleware     | Y.200–Y.299 |
+| Network aspects                           | Y.300–Y.399 |
+| Interfaces and protocols                  | Y.400–Y.499 |
+| Numbering, addressing and naming          | Y.500–Y.599 |
+| Operation, administration and maintenance | Y.600–Y.699 |
+| Security                                  | Y.700–Y.799 |
+| Performances                              | Y.800–Y.899 |
+
+## INTERNET PROTOCOL ASPECTS
+
+|                                                                           |                      |
+|---------------------------------------------------------------------------|----------------------|
+| General                                                                   | Y.1000–Y.1099        |
+| Services and applications                                                 | Y.1100–Y.1199        |
+| <b>Architecture, access, network capabilities and resource management</b> | <b>Y.1200–Y.1299</b> |
+| Transport                                                                 | Y.1300–Y.1399        |
+| Interworking                                                              | Y.1400–Y.1499        |
+| Quality of service and network performance                                | Y.1500–Y.1599        |
+| Signalling                                                                | Y.1600–Y.1699        |
+| Operation, administration and maintenance                                 | Y.1700–Y.1799        |
+| Charging                                                                  | Y.1800–Y.1899        |
+| IPTV over NGN                                                             | Y.1900–Y.1999        |
+
+## NEXT GENERATION NETWORKS
+
+|                                                                   |               |
+|-------------------------------------------------------------------|---------------|
+| Frameworks and functional architecture models                     | Y.2000–Y.2099 |
+| Quality of Service and performance                                | Y.2100–Y.2199 |
+| Service aspects: Service capabilities and service architecture    | Y.2200–Y.2249 |
+| Service aspects: Interoperability of services and networks in NGN | Y.2250–Y.2299 |
+| Enhancements to NGN                                               | Y.2300–Y.2399 |
+| Network management                                                | Y.2400–Y.2499 |
+| Network control architectures and protocols                       | Y.2500–Y.2599 |
+| Packet-based Networks                                             | Y.2600–Y.2699 |
+| Security                                                          | Y.2700–Y.2799 |
+| Generalized mobility                                              | Y.2800–Y.2899 |
+| Carrier grade open environment                                    | Y.2900–Y.2999 |
+
+## FUTURE NETWORKS
+
+|                 |               |
+|-----------------|---------------|
+| CLOUD COMPUTING | Y.3500–Y.3999 |
+|-----------------|---------------|
+
+*For further details, please refer to the list of ITU-T Recommendations.*
+
+# Recommendation ITU-T Y.1271
+
+# **Framework(s) on network requirements and capabilities to support emergency telecommunications over evolving circuit-switched and packet-switched networks**
+
+## **Summary**
+
+Many challenges and considerations need to be addressed in defining and establishing the functional capabilities to support emergency telecommunications in evolving circuit- and packet-switched telecommunications networks. This Recommendation presents an overview of the basic requirements, features, and concepts for emergency telecommunications that evolving networks are capable of providing.
+
+## **History**
+
+| Edition | Recommendation | Approval   | Study Group | Unique ID*                                                                |
+|---------|----------------|------------|-------------|---------------------------------------------------------------------------|
+| 1.0     | ITU-T Y.1271   | 2004-10-14 | 13          | <a href="http://handle.itu.int/11.1002/1000/7047">11.1002/1000/7047</a>   |
+| 2.0     | ITU-T Y.1271   | 2014-07-18 | 13          | <a href="http://handle.itu.int/11.1002/1000/12177">11.1002/1000/12177</a> |
+
+---
+
+\* To access the Recommendation, type the URL <http://handle.itu.int/> in the address field of your web browser, followed by the Recommendation's unique ID. For example, <http://handle.itu.int/11.1002/1000/11830-en>.
+
+## FOREWORD
+
+The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis.
+
+The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics.
+
+The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1.
+
+In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC.
+
+## NOTE
+
+In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency.
+
+Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party.
+
+## INTELLECTUAL PROPERTY RIGHTS
+
+ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process.
+
+As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at <http://www.itu.int/ITU-T/ipr/>.
+
+© ITU 2014
+
+All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU.
+
+## Table of Contents
+
+|   |                                                                                    | Page |
+|---|------------------------------------------------------------------------------------|------|
+| 1 | Scope.....                                                                         | 1    |
+| 2 | References.....                                                                    | 1    |
+| 3 | Definitions .....                                                                  | 2    |
+|   | 3.1 Terms defined elsewhere.....                                                   | 2    |
+|   | 3.2 Terms defined in this Recommendation.....                                      | 2    |
+| 4 | Abbreviations and acronyms .....                                                   | 4    |
+| 5 | Security.....                                                                      | 4    |
+| 6 | Consideration.....                                                                 | 4    |
+|   | 6.1 The nature of emergency situations.....                                        | 4    |
+|   | 6.2 Emergency response .....                                                       | 5    |
+|   | 6.3 Assured telecommunications.....                                                | 5    |
+| 7 | Emergency telecommunications requirements and capabilities .....                   | 6    |
+|   | 7.1 Enhanced priority treatment .....                                              | 6    |
+|   | 7.2 Secure networks.....                                                           | 8    |
+|   | 7.3 Location confidentiality.....                                                  | 9    |
+|   | 7.4 Restorability .....                                                            | 9    |
+|   | 7.5 Network connectivity .....                                                     | 9    |
+|   | 7.6 Interoperability .....                                                         | 10   |
+|   | 7.7 Mobility .....                                                                 | 10   |
+|   | 7.8 Ubiquitous coverage.....                                                       | 10   |
+|   | 7.9 Survivability/endurability .....                                               | 10   |
+|   | 7.10 Voice transmission .....                                                      | 11   |
+|   | 7.11 Video transmission .....                                                      | 11   |
+|   | 7.12 Data transmission .....                                                       | 11   |
+|   | 7.13 Scaleable bandwidth.....                                                      | 12   |
+|   | 7.14 Preferential treatment in congestion control mechanisms.....                  | 12   |
+|   | 7.15 Reliability/availability .....                                                | 13   |
+|   | 7.16 ETS use of cloud infrastructure.....                                          | 14   |
+|   | Annex A – A possible distinction between essential and optional requirements ..... | 15   |
+|   | Appendix I – Information on possible sources of disasters .....                    | 17   |
+|   | Bibliography.....                                                                  | 19   |
+
+## **Introduction**
+
+The purpose of emergency telecommunications is to facilitate emergency recovery operations with the goal for restoring the community infrastructure and for returning the population to normal living conditions after serious disasters. In some countries, emergency recovery operations are considered to fall within the scope of public safety organizations. Responders need to assess the damage, coordinate rescue and medical assistance, harmonize restoration endeavours, etc. For supporting this purpose, emergency telecommunications may be provided through shared resources from the public telecommunications infrastructure, and in some cases through additional resources of enterprise networks (e.g., the public safety network), that are evolving from a basic circuit-switched to packet-switched networks with a variety of telecommunication capabilities.
+
+# Recommendation ITU-T Y.1271
+
+## Framework(s) on network requirements and capabilities to support emergency telecommunications over evolving circuit-switched and packet-switched networks
+
+## 1 Scope
+
+Contextual understanding and careful thought is required to address the unique challenges faced by emergency telecommunications. This Recommendation presents an overview of the basic requirements, features, and concepts for emergency telecommunications that evolving telecommunication networks are capable of providing. This Recommendation provides guidance to telecommunication network operators on network requirements and capabilities to support emergency telecommunications offerings and to provide responders (users) with useful information for (acquisitions) request of such capabilities.
+
+NOTE – This Recommendation defines requirements for networks which when implemented should help support emergency telecommunication services and facilitate the application of [ITU-T E.106] and [ITU-T E.107] if needed.
+
+## 2 References
+
+The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation.
+
+- [ITU-T E.106] Recommendation ITU-T E.106 (2003), *International Emergency Preference Scheme (IEPS) for disaster relief operations.*
+- [ITU-T E.107] Recommendation ITU-T E.107 (2007), *Emergency Telecommunications Service (ETS) and interconnection framework for national implementations of ETS.*
+- [ITU-T J.260] Recommendation ITU-T J.260 (2005), *Requirements for preferential telecommunications over IPCablecom networks.*
+- [ITU-T J.261] Recommendation ITU-T J.261 (2009), *Framework for implementing preferential telecommunications in IPCablecom and IPCablecom2 networks.*
+- [ITU-T M.3342] Recommendation ITU-T M.3342 (2006), *Guidelines for the definition of SLA representation templates.*
+- [ITU-T X.1303] Recommendation ITU-T X.1303 (2007), *Common alerting protocol (CAP 1.1).*
+- [ITU-T Y.2001] Recommendation ITU-T Y.2001 (2004), *General overview of NGN.*
+- [ITU-T Y.2205] Recommendation ITU-T Y.2205 (2011), *Next Generation Networks – Emergency telecommunications – Technical considerations.*
+- [ITU-T Y.3501] Recommendation ITU-T Y.3501 (2013), *Cloud computing framework and high-level requirements.*
+- [ITU-T Y.3510] Recommendation ITU-T Y.3510 (2013), *Cloud computing infrastructure requirements.*
+
+- [ITU-T Y.3520] Recommendation ITU-T Y.3520 (2013), *Cloud computing framework for end to end resource management*.
+- [ATIS-1000057] ATIS-1000057 (2014), *Service Requirements for Emergency Telecommunications Service (ETS) in Next Generation Network (NGN)*.
+- [ETSI TS 122 011] ETSI TS 122 011 (2013), *Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; Service accessibility (3GPP TS 22.011 version 11.3.0 Release 11)*.
+- [ETSI TS 133 401] ETSI TS 133 401 (2013), *Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; 3GPP System Architecture Evolution (SAE); Security architecture (3GPP TS 33.401 version 11.7.0 Release 11)*.
+- [IETF RFC 4412] IETF RFC 4412 (2006), *Communications Resource Priority for the Session Initiation Protocol (SIP)*.
+- [IETF RFC 5321] IETF RFC 5321 (2008), *Simple Mail Transfer Protocol*.
+- [IETF RFC 5670] IETF RFC 5670 (2009), *Metering and Marking Behaviour of PCN-Nodes*.
+- [IETF RFC 6679] IETF RFC 6679 (2012), *Explicit Congestion Notification (ECN) for RTP over UDP*.
+- [IETF RFC 6710] IETF RFC 6710 (2012), *Simple Mail Transfer Protocol Extension for Message Transfer Priorities*.
+
+## 3 Definitions
+
+### 3.1 Terms defined elsewhere
+
+This Recommendation uses the following terms defined elsewhere:
+
+**3.1.1 Emergency Telecommunications Service (ETS)** [ITU-T E.107]: A national service providing priority telecommunications to the ETS authorized users in times of disaster and emergencies.
+
+**3.1.2 next generation network (NGN)** [ITU-T Y.2001]: A packet-based network able to provide telecommunication services and able to make use of multiple broadband, QoS-enabled transport technologies and in which service-related functions are independent from underlying transport related technologies. It enables unfettered access for users to networks and to competing service providers and/or services of their choice. It supports generalized mobility which will allow consistent and ubiquitous provision of services to users.
+
+### 3.2 Terms defined in this Recommendation
+
+This Recommendation defines the following terms:
+
+**3.2.1 assured capabilities:** Capabilities providing high confidence or certainty that critical telecommunications are available and perform reliably.
+
+**3.2.2 authentication:** The act or method used to verify a claimed identity.
+
+**3.2.3 authorization:** The act of determining if a particular privilege, such as access to telecommunications resource, can be granted to the presenter of a particular credential.
+
+**3.2.4 authorized emergency telecommunication user:** A person or an organization authorized to obtain premium privileges and capabilities in national and/or international emergency situations.
+
+**3.2.5 bottom-up emergency declaration:** An emergency declaration determined or assumed by individual users. The user or users would then use emergency telecommunications according to individual authorizations or authorities.
+
+**3.2.6 buffer-bloat:** A situation in a packet-switched network whereby large buffers at various network nodes and end systems cause excessive latency and jitter, as well as reduce the overall network performance. This situation may affect how quickly emergency situations are communicated.
+
+**3.2.7 confined emergency situation:** An emergency situation within a certain defined relatively small geographic area (e.g., local) not affecting other areas.
+
+**3.2.8 declared emergency situation:** An emergency publicly recognized and stated by a responsible authoritative official(s) of the responsible government(s).
+
+**3.2.9 emergency situation:** A situation, of serious nature, that develops suddenly and unexpectedly. Extensive immediate important efforts, facilitated by telecommunications, may be required to restore a state of normality to avoid further risk to people or property. If this situation escalates, it may become a crisis and/or disaster.
+
+**3.2.10 international emergency situation:** An emergency situation, across international boundaries, that affects more than one country.
+
+**3.2.11 label:** An identifier occurring within or attached to data elements.
+
+**3.2.12 nationwide emergency situation:** An emergency situation that affects an entire nation, but remains confined in scope to only one country.
+
+**3.2.13 ordinary emergency capability:** A special emergency type of telecommunications capability (such as 911, 110, or 112) used on a national level made available to the general public to report local or personal emergencies to government officials or other officially designated civil authorities.
+
+**3.2.14 policy:** Rules (or methods) for allocating telecommunication network resources among types of traffic that may be differentiated by labels.
+
+**3.2.15 precedence:** When a privilege exists to enable, or facilitate, the preceding of others.
+
+**3.2.16 preferential:** A capability offering advantage over regular capabilities.
+
+**3.2.17 preferential treatment in congestion control mechanisms:** Methodologies to manage telecommunication resources to minimize the impact of congestion on emergency telecommunications. Congestion can be managed via a number of measures, such as network design, network element mechanisms (e.g., machine congestion controls) and network operational capabilities.
+
+**3.2.18 priority treatment capabilities:** Capabilities that provide premium access to, and/or use of telecommunications network resources.
+
+**3.2.19 public safety:** An umbrella term used in some regions to encompass emergency recovery operations along with other services such as fire and rescue, ambulance and emergency medical services, police and security guard licensing services, etc. for the welfare and protection of the general public. The primary goal is prevention, and protection of the public from dangers affecting safety such as crimes or disasters.
+
+**3.2.20 top down emergency declaration:** When responsible official(s) with recognized authority in Government, or industry issue an emergency declaration.
+
+## **4 Abbreviations and acronyms**
+
+This Recommendation uses the following abbreviations and acronyms:
+
+|      |                                      |
+|------|--------------------------------------|
+| CSP  | Cloud Service Provider               |
+| DSL  | Digital Subscriber Line              |
+| ETS  | Emergency Telecommunications Service |
+| GBR  | Guaranteed Bit Rate                  |
+| IM   | Instant Messaging                    |
+| IMS  | IP Multimedia Subsystem              |
+| KQI  | Key Quality Indicator                |
+| LTE  | Long Term Evolution                  |
+| NGN  | Next Generation Network              |
+| QoS  | Quality of Service                   |
+| RACH | Random Access Channel                |
+| RAN  | Radio Access Network                 |
+| SLA  | Service Level Agreement              |
+| SLS  | Service Level Specification          |
+| SMS  | Short Message Service                |
+| SMTP | Simple Mail Transfer Protocol        |
+| SP   | Service Provider                     |
+
+## **5 Security**
+
+Due to the nature of this Recommendation, security is addressed in general. However, special attention should be given to clause 6.3 and clause 7 where several requirements may have strong security implications, such as authorization (clause 6.3), network integrity (clause 7.2), secrecy aspects of selected users (clause 7.3), network restorability (clause 7.4), interoperability (clause 7.6), survivability/endurability (clause 7.9) and reliability/availability (clause 7.15). Other ITU-T Recommendations may complete this Recommendation with regard to security aspects.
+
+## **6 Consideration**
+
+### **6.1 The nature of emergency situations**
+
+Disasters often happen as sudden events that cause immense damage, loss and destruction. Disaster events occur due to the forces of nature or because of actions that stem from human sources or interventions. Disasters can have extreme magnitude, be long lasting, and cover wide geographic areas within national or international boundaries. In other words, disasters are variable in magnitude (energy), duration (time) and geographic area.
+
+Hundreds of disasters occur each year all over the world; no country is immune. A confined disaster may be quite severe and yet by definition is local in nature. Disasters may affect an entire region, such as with nationwide or international emergency situations. Each disaster brings suffering, financial and social consequences. Regardless of the kind of disaster, telecommunications are needed to respond effectively and save lives.
+
+In most countries plans and measures (e.g., tests, exercises and drills) are designed and deployed to anticipate and effectively address disasters. However, sometimes a scenario known as "black swan" may occur. An unusual combination of abnormal conditions may challenge or defy traditional disaster anticipation and mitigation.
+
+### **6.2 Emergency response**
+
+All types of disasters, whether attributed to natural or human sources, can strike anywhere and at any time. Disaster recovery occurs in stages. The first responders to a disaster scene play the primary role in assessing and containing the damage. Other phases follow in quick succession. In the second phase the injured are treated and the saving of lives is priority. The third stage often brings additional disaster recovery personnel, equipment and supplies, perhaps from pre-positioned sites, storage facilities or staging areas. The fourth phase comprises clean-up and restoration.
+
+The common thread to facilitate operations for all disaster recovery phases is the utility of fast, reliable, user-friendly emergency telecommunications that may be realized by technical solutions and/or administrative policy. It should be realized that some of the existing plans initially accounted for adversities that were greater than these response measures – for example, earthquakes may be stronger than the measures that were planned for them.
+
+### **6.3 Assured telecommunications**
+
+The goal is assured telecommunication capabilities during emergency situations. Disasters can impact telecommunications infrastructures themselves. Typical impacts may include: congestion overload and the need to re-deploy or extend telecommunications capabilities to new geographic areas not covered by existing infrastructures. Even when telecommunications infrastructures are not damaged by the disaster, demand for telecommunications soar during such events.
+
+The method by which authorities are notified of an emergency situation varies widely. Citizens using an ordinary emergency capability may notify authorities of a disaster. Alternatively, emergency workers that are directly or indirectly interacting with people in the disaster area may make a bottom-up emergency declaration. This information may result in an authoritative official(s) of the responsible government issuing a declared emergency. The latter represents a top down emergency declaration.
+
+The affiliation of an emergency worker may be known in advance of an actual emergency situation. In this case, their credentials may be stored thereby allowing the person to be authenticated for an authorized telecommunication. Generally, when preferential or priority treatment telecommunication capabilities (e.g., to enable precedence over other users) are offered, users of the service need to be authorized and authenticated. Whether authorization is required shall be national matters of the respective particular country. However, without authorization, preferential treatment capabilities may be subject to abuse by non-authorized individuals. Technical considerations for security are discussed in clause 11 of [ITU-T Y.2205].
+
+Circuit-switched and some packet-switched (next generation network [NGN]) networks respond to overload situations by denying call attempt when resources are saturated. Some networks will provide preferential treatment to call requests. One option is to pre-empt other callers when authorized emergency communication workers need to communicate. However, some types of packet-switched networks respond to additional load by degrading performance of individual user traffic in the entire network. This occurs when networks operate under a best-effort framework where all information is treated the same and simply queued or dropped until network resources are available.
+
+Recent studies and measurements indicate that a phenomenon referred to as "buffer-bloat" may introduce unacceptable latency. The reduction in cost of memory has resulted in network resources (including end-user equipment in broadband networks) having large buffers. These buffers result in delaying timely congestion notifications that are meant to minimize the impact of congestion. These
+
+large buffers may impact not only the best-effort traffic, but also priority traffic such as that of emergency telecommunications.
+
+Providing a preferential treatment to emergency telecommunications and by providing fault tolerant networks that will not fail because any one component fails are important steps toward assured capabilities. While fault tolerant networks are a critical step toward assured capabilities, telecommunications network operators should also maintain recovery plans to restore networks in the event of failure.
+
+## 7 Emergency telecommunications requirements and capabilities
+
+Fully comprehensive emergency telecommunications need to have many capabilities to support a variety of operational requirements for emergency recovery forces. Table 1, as shown below, lists specific objectives and requirements that could potentially facilitate telecommunications for disaster recovery activities. Implementing these requirements into operational capabilities greatly facilitates effective and timely recovery operations during emergency events.
+
+NOTE – Where solutions to such requirements are implemented, they could also be used to support ordinary emergency services like traditional 110, 112, 911 and so on. Requests to meet particular requirements and the conditions thereof shall be national matters of the respective country.
+
+Table 1 provides objectives and functional requirements.
+
+**Table 1 – Emergency telecommunications functional requirements and capabilities**
+
+|                                                         |
+|---------------------------------------------------------|
+| Enhanced priority treatment                             |
+| Secure networks                                         |
+| Location confidentiality                                |
+| Restorability                                           |
+| Network connectivity                                    |
+| Interoperability                                        |
+| Mobility                                                |
+| Ubiquitous coverage                                     |
+| Survivability/endurability                              |
+| Voice transmission                                      |
+| Video transmission                                      |
+| Data transmission                                       |
+| Scaleable bandwidth                                     |
+| Reliability/availability                                |
+| Preferential treatment in congestion control mechanisms |
+
+### 7.1 Enhanced priority treatment
+
+Emergency telecommunication traffic needs assured capabilities regardless of the networks traversed. A prime component of assured capabilities is enhanced priority treatment. One potential method to achieve priority treatment is to first "identify" (e.g., classify and/or label) emergency traffic and then apply network policy to this traffic in order to achieve the desired assured service. In connection-oriented transport, once a connection is established, the call effectively is "hard wired", has guaranteed performance and does not necessarily require continuance of preferential status. With connectionless packet-switched transport, however, it may be necessary to maintain the emergency telecommunication identification for each packet. Telecommunication network operators and service providers (SPs) need to be able to identify and prioritize emergency telecommunications according to their SLA with users.
+
+New or temporary emergency operations users require a network operator to provision an access line<sup>1</sup>. It is desirable for provisioning to occur on a preferential basis to enable rapid initiation of emergency telecommunications.
+
+#### **7.1.1 Preferential access to telecommunications facilities**
+
+There are a number of ways to access telecommunication resources for obtaining emergency telecommunication capabilities. These include analogue subscriber line, wireless, satellite, cable, digital subscriber line (DSL), and optical fibre. There will be a significant advantage for an emergency operations user to be able to obtain access to these various telecommunications network services on a priority or preferential basis. This will enable more rapid initiation of emergency telecommunications.
+
+The traditional circuit-switched network regularly has no general provision for signalling priority access requests. However, specially marked lines or specifically provisioned "off-hook" services could provide preferential access, but that would only be by line and location and not per emergency telecommunication request. There is currently no provision for conveying a priority dial tone or service initiation via general access from a conventional telephone instrument. A dial tone comes on a demand basis from a limited selection of ports and heavy traffic conditions can delay access if demand consumes the supply of ports. Therefore, a provision for preferential access to services in evolving networks is a capability that requires consideration.
+
+#### **7.1.2 Preferential establishment, use of remaining operational resources and completion of emergency traffic**
+
+Emergency traffic needs to be identified in order to distinguish this type of traffic with respect to ordinary traffic. With traditional circuit-switched networks, only the signalling protocol is able to distinguish the two traffic types. However, in packet-switched networks, identification through the use of labels in either signalling or data elements can facilitate distinguishing types of traffic. In packet-switched networks, labels can reside in different layers or sublayers.
+
+Once traffic is identified, telecommunication network policy rules or methods should be applied to provide an enhanced priority treatment to emergency traffic. With connection-oriented transport, the policy potentially includes a higher probability of call admission. With connectionless oriented transport, the policy needs to provide a higher probability of success relative to the success of the routing and delivery of ordinary traffic.
+
+##### **7.1.2.1 Completion of emergency traffic during congestion**
+
+Emergency traffic needs to be minimally impacted during network congestion. Traditional circuit-switched networks applied traffic control methods such as call blocking to reduce congestion on the networks. Emergency traffic is distinguished by minimizing blocking and ensuring a high probability of call completion over normal traffic.
+
+In packet-switched NGN, priority signalling, priority transport of signalling and media and various preferential treatment mechanisms (including congestion control mechanisms) for emergency traffic are used to prevent blocking and ensure a high probability of completion of emergency traffic, as compared to normal traffic.
+
+##### **7.1.2.2 Exemption from network management controls**
+
+Based on regional/national requirements and network operator policy, emergency telecommunications should be exempted from network management controls up to the point where further exemption would cause network instability. Congestion controls (e.g., machine congestion
+
+---
+
+<sup>1</sup> If access line is used in this context, it means a wired as well as wireless access, channel, virtual connection, tunnel, etc.
+
+controls), overload controls and load balancing should not adversely impact emergency telecommunications.
+
+#### **7.1.3 Preferential routing of emergency telecommunication traffic**
+
+In some situations, emergency traffic could be redirected to alternate paths when default paths have become unusable or congested. In evolving networks, it is desirable for emergency telecommunications to avoid single points of failure and hence possibly have multiple backup paths or alternate routing for use during periods of overload or failed connections through the network. In packet-based networks, routing of packets is a continuing process for an instance of telecommunication until the session has reached completion. As a result, the traffic monitoring and network controls should be continuous to avoid the impacts of overloaded connections and systems. In addition, the effect of large buffer overloads may shift across the different elements of the network with the variation of available actual bandwidth. Thus constant monitoring and controls are required to manage the buffers and avoid high latency for the emergency traffic.
+
+In addition, several new congestion avoidance techniques (as opposed to congestion control) have emerged in recent years that can be deployed to support users of emergency telecommunications [IETF RFC 4412], [b-IETF RFC 5559], [IETF RFC 5670] and [IETF RFC 6679].
+
+#### **7.1.4 Optional pre-emption of non-emergency traffic**
+
+While the concept of pre-emption typically applies to circuit-switched communications, its application in some packet-switched (NGN) networks is also defined. Pre-emption of non-emergency traffic to free bandwidth and resources for emergency traffic is an optional requirement; the basic emergency telecommunications provisions do not include the concept of pre-emption. However, using labels to prioritize emergency traffic is one approach to identify and make available resources for emergency traffic over normal traffic.
+
+#### **7.1.5 Allowable degradation of service quality for traffic, as infrastructure resources become unavailable**
+
+The QoS for different modes of service for the emergency telecommunications would typically be designated as the best available to ensure clear clean telecommunications and conveyance of important information. However, when the telecommunication resources are experiencing severe stress, an allowable degradation of QoS may be acceptable. This could occur only when resources have become unavailable to the point that the network cannot support non-emergency traffic and sufficient bandwidth and resources are not available to support the normally acceptable QoS level for emergency traffic. Rather than lose the ability to communicate, emergency operations need to continue to convey critical information, even if constrained.
+
+In justified cases during declared emergency situations where telecommunications infrastructure resources are leading to exhaustion, then it may be necessary to give emergency telecommunications priority over the ordinary telecommunications. This may affect established telecommunications in terms of QoS. As a result, ordinary telecommunications in progress may be degraded or released.
+
+### **7.2 Secure networks**
+
+Security protection is necessary to prevent unauthorized users from obtaining scarce telecommunication resources needed to support emergency operations.
+
+#### **7.2.1 Rapid authentication of authorized users for emergency telecommunications**
+
+The emergency telecommunications is intended only for authorized users who participate in emergency recovery operations. The appropriate authority of each nation or community may authorize these designated users. Upon initiation of an emergency communication request, for evolving networks, it is desirable to request to establish an innovative method for a streamlined rapid user authentication process in these evolving telecommunication networks, including mobile
+
+networks which verifies the user's identity to protect the telecommunication resources against excessive use and abuse during an emergency situation. Once an authentication is validated and emergency telecommunication travels across networks, such authentication information may be associated with labels that then should be transported from the call initiation until termination. It may be necessary for the label to remain throughout the duration of the emergency call.
+
+#### **7.2.2 Security protection of emergency telecommunication traffic**
+
+In addition to authentication and authorization, other aspects of security such as measures against spoofing, intrusion and denial of service are required for emergency telecommunications. It is desirable to offer assurance that unauthorized modifications of objects may be detected. Ordinary telecommunications may then also benefit from increased protection from intrusion and denial-of-service attacks. Networks should have protection against (fraud) corruption of, or unauthorized access to, traffic and control, including expanded encryption techniques and user authentication, as appropriate.
+
+### **7.3 Location confidentiality**
+
+For certain emergency telecommunications, special additional security measures may apply. For example, in one potential destructive scenario is the trial to obstruct disaster recovery operations themselves. In such a scenario, emergency telecommunications from selected users need to be protected from manipulation, interception or obstruction by others, due to their urgent and important nature. Special security mechanisms to prevent the identification of the location of certain authorized users of emergency telecommunications from being revealed to non-authorized parties should apply in order to protect such authorized users from being located. These special security requirements are beyond the scope of this framework Recommendation.
+
+A limited number of high level leadership emergency telecommunications users may need to organize emergency relief operations without risk of their location being discovered.
+
+### **7.4 Restorability**
+
+If network capabilities key to emergency operations fail, those capabilities need to be restored in a timely fashion. Both circuit- and packet-switched networks typically require a physical access line, wired or wireless, that extends to customer locations. When access lines are damaged, network operators restore operations but access disruption times may be lengthy. Therefore, it is necessary for restoration to occur on a preferential basis to enable rapid initiation of emergency telecommunications for users of these capabilities.
+
+Should a disruption occur, telecommunication network functionalities should be capable of being reprovisioned, repaired, or restored to required levels on a priority basis.
+
+### **7.5 Network connectivity**
+
+It is advisable that networks supporting emergency telecommunications be connected to other networks thereby providing a wide reach. Interworking preferential treatment at reference points that are deemed to constitute international and/or regulatory boundaries between national networks that provide emergency telecommunications may create international emergency systems, e.g., when [ITU-T E.106] and/or [ITU-T E.107] is applicable.
+
+NOTE – Disaster situations are often regional but may include multiple nations. In these cases, disaster recovery emergency telecommunications from multiple nations may be necessary to respond to one specific event. Also, in the "increasingly networked world", many nations often provide support for recovery operations for emergency disasters contained within the borders of a stricken country.
+
+In certain liberalized and competitive environments, there may be:
+
+- a) more than one network operator in a given country;
+- b) network operators whose networks span more than one country.
+
+In these cases, consideration needs to be given to the interconnection of emergency telecommunications capabilities between network operator boundaries and/or across reference points which constitute national and/or regulatory boundaries.
+
+### **7.6 Interoperability**
+
+Evolving networks will produce a number of issues, one of which is to ensure orderly and transparent continuance of the basic ITU-T E.106 emergency preference capabilities. During the convergence period, the different schemes for interworking between the circuit-switched and packet-switched technologies need to be considered. For example, voice calls from the telephone or mobile network may transit packet-switched networks and then terminate in either the circuit-switched network or directly in a packet-switched network. Interworking requirements for preferential treatment methods over heterogeneous networks have been addressed for PSTN and IP-Cablecom networks in clause 6 of [ITU-T J.261] and clause 6.2 of [ITU-T J.260]. These requirements may also be applied to other heterogeneous networks.
+
+Configuration issues are often a major cause of interoperability problems. In order to have interoperable capabilities among different operators offering emergency telecommunications, a common configuration will be helpful. Note this does not imply operators must all configure their internal networks the same if they are to support emergency capabilities. It only implies they will translate appropriate configurations at the appropriate ingress/egress locations. This method also allows more ubiquity because any emergency service may be initiated with any contracted SP without configuration modification.
+
+The goal of this requirement is to provide interconnection and interoperability among all networks (evolving or existing).
+
+### **7.7 Mobility**
+
+Mobility calls for a telecommunications infrastructure that is integrated with transportable, re-deployable and fully mobile facilities. In order to have mobile capabilities, a common configuration provides key elements to facilitate capabilities for emergency applications. The telecommunications infrastructure should support user and terminal mobility including re-deployable, or fully mobile telecommunications. With most wireless terminals supporting both WiFi and cellular technologies, data off-loading to enable increased voice traffic on mobile networks is gaining importance. The emergency traffic may be voice or data and these off-loading capabilities should provide preferential treatment to both voice and data traffic.
+
+### **7.8 Ubiquitous coverage**
+
+Ubiquitous telecommunications resources that provide support to services of the general population may provide the basis for readily available capabilities for emergency telecommunications. Because these capabilities are at hand, emergency operations activities do not need to wait for deployment of special facilities. However, in situations where networks do not (or may not) support emergency communication requirements/capabilities, then emergency communication users will default to communication capabilities available to the general public.
+
+Therefore, public telecommunication infrastructure resources over large geographic areas should form the framework for ubiquitous coverage of emergency telecommunications.
+
+### **7.9 Survivability/endurability**
+
+Key network infrastructure supporting emergency telecommunications needs to be as robust as possible so as to endure throughout the disaster.
+
+Capabilities should be robust to support surviving users under a broad range of circumstances, from the widespread damage of a natural or human-made disaster.
+
+### **7.10 Voice transmission**
+
+Traditionally, the fundamental telecommunications method for emergency recovery has been and will continue to be voice communications. Hence, networks need voice transmission capabilities for emergency operations. Circuit-switched networks provide this by default while packet-switched networks require support of: low jitter, low loss and low delay for acceptable interactive real time voice media streams. Circuit-switched and packet-switched networks should provide voice transmission quality service for emergency telecommunications users.
+
+### **7.11 Video transmission**
+
+In addition to voice communications, interactive video communications are becoming an increasing important tool for emergency recovery operations. Within packet-switched networks, video services can be delivered over the same session-oriented reference architecture used for voice, including similar signalling. However, video includes audio and video components that may involve very different network bandwidth and performance requirements from that of voice, and may be used in different modes from those generally thought of for voice, e.g., two-way audio conversations with two-way video, or two-way audio conversations with one-way video. Video services used for emergency recovery could become part of a priority video conferencing service offered by a service provider.
+
+### **7.12 Data transmission**
+
+In addition to voice transmission, the fundamental, ubiquitous presence of Internet has resulted in increasing packet based voice and data transmission capabilities. Many service providers offer voice, video and data communications over their managed data network that provide for multimedia communications to various devices ranging from hand-held mobile terminals to fixed terminals located in residences and enterprises. These communication methods offer more choices for emergency telecommunications users both as alternative paths of communication and alternative methods to reach areas that may have damaged infrastructure. The Quality of Service (QoS) for emergency telecommunications, based on the standards, should be maintained as much as possible. The QoS in terms of minimum loss of packets should be provided by the data networks in such a scenario.
+
+[ATIS-1000057] describes examples of two types of data services that may be used to support emergency recovery: guaranteed bit rate (GBR) data service, and data transport (non-GBR). In addition to these, the broader family of data services used in support emergency recovery operations may include prioritized versions of the following commercial services: web service, file transfer, e-mail, short message service (SMS) over IP and instant messaging (IM).
+
+For e-mail, a widely used method involves using the Simple Mail Transfer Protocol (SMTP). Even though different approaches have been used to indicate in the header fields such as importance and priority, these approaches (methodologies) often present widely varying syntax, and consequently, SMTP receivers deal with these approaches differently. Nevertheless, a standard approach may be applied during message submission: reference Message Submission for Mail [b-IETF RFC 6409], and reference Simple Mail Transfer Protocol [IETF RFC 5321] for transfer, but with two IETF options as follows: (1) by defining a priority parameter in the "Mail From" command with a set of integer values designating the priority level, and (2) by defining an extension to the SMTP header which is used when relaying a message through transfer agents that do not support the parameter discussed in (1) [IETF RFC 6710]. Even though the actual values and semantics of the priority depend on the policies in place, an example set of values are included for the case when a set of authorized users use SMTP to communicate emergency telecommunications services. The principles for handling the priority parameter or header defined by this approach may be considered for adoption as the nodes of the network are deployed with these extensions.
+
+Another data communications example is the need to exchange alerts from authorities to citizens related to large-scale emergencies such as tsunami warnings and other natural or man-made disasters using mechanisms such as a common alerting protocol [ITU-T X.1303]. There are two phases present in this type of communication. In the first phase, the alerts may be subscription based such as school closures sent to parents, or sent to those residing in a specific geographic area as in the case of tsunami warnings without an explicit subscription. The second phase relates to the reliable delivery of alerts.
+
+### **7.13 Scaleable bandwidth**
+
+In justified cases during declared emergency situations where infrastructure resources are leading to exhaustion, then it may be necessary to give emergency telecommunications priority over the ordinary telecommunications. One method to achieve this is to allow emergency telecommunications scalable bandwidth to enable reducing the bandwidth available for ordinary telecommunications and thus potentially affect established telecommunications in terms of QoS. Ordinary telecommunications may be degraded or released thereby to an allowable degradation of service quality for non-emergency telecommunication traffic, as infrastructure resources become unavailable.
+
+Broadband is a user requirement that may be requested during acquisitions of emergency telecommunications from operators. Authorized users should be able to select the capabilities of emergency telecommunications to support variable bandwidth requirements.
+
+### **7.14 Preferential treatment in congestion control mechanisms**
+
+In the case of packet networks, many of the edge and core routes are configured with thresholds and congestion control mechanisms to reduce the level of congestion. These mechanisms result in dropped packets for both normal and priority traffic depending on the level of congestion. Even though the emergency telecommunications may be given a higher priority than best-effort traffic, the mechanisms, if applied to all traffic, may throttle emergency telecommunications. These congestion control mechanisms should be configured such that authorized emergency telecommunication users' traffic continues to communicate even at a degraded level without being subject to these mechanisms.
+
+When signalling support is available, for example, the resource priority header field in SIP, the types of traffic can be identified. Labels are also included to distinguish the priority of different types of traffic. The congestion control mechanisms should be able to recognize the emergency traffic and offer exemptions to minimize dropped packets for such traffic. Emergency traffic should have reduced measures applied compared to normal traffic during congestion.
+
+In next generation mobile and fixed networks, the use of an IP multimedia subsystem (IMS) has gained importance, especially with respect to radio access networks (RANs) such as long-term evolution (LTE) networks. For mobile access, the user equipment for authorized emergency telecommunication users is configured with an access class overload protection code to gain priority access on the random access channel (RACH) during congestion. Network elements such as base station, MME and gateway support signalling parameters (such as advanced priority) during congestion to provide prioritization of emergency telecommunications during congestion. [ETSI TS 133 401] and [ETSI TS 122 011] describe evolving 3GPP system architecture for security and the access class barring overload protection, respectively.
+
+From the service provider's perspective three metrics are commonly used to manage traffic in the presence of congestion: rate-based, volume-based and application-based. Some of the limitations of these approaches include over or under constraining the network and policy concerns resulting from application-layer security support (encryption). In order for the operator to perform the application agnostic metric and overcome performance uncertainty, there is support from operators for the sender to provide congestion exposure signals in addition to congestion notification feedback from the receiver. The sender includes expected congestion in the header of the data and the intermediate nodes learn about the congestion on the path from the header information. The operator can monitor these
+
+exposure signals specifically under abnormal conditions and take the necessary action to improve the probability of completion for Emergency Telecommunications Service (ETS) traffic.
+
+Emergency traffic should not experience high latency. For example, the phenomenon described above that has been found by actual measurements is the increased latency resulting from large buffers in the network. During congestion, the impact of these large buffers negates the usefulness of the congestion control. Configuring, monitoring and managing these buffers at all points in the networks are crucial to have a high probability of success with acceptable latency.
+
+In managing these buffers, certain characteristics that are important for efficient active queue management have been identified [b-Nichols]. A controlled delay management is to be considered based on minimum queue size instead of average queue size, a state variable to track the minimum queue size and the time packet remaining in the queue. These are considered to be better measures to manage large buffers than, for example, thresholds on queue size and link utilization that are used currently. Understanding queue management and deploying appropriate measures combined with delay-bound per-hop behaviour are likely to mitigate high latency for emergency telecommunications traffic.
+
+The networks should be designed and maintained, using various available mechanisms, such that the standardized QoS is maintained as much as possible.
+
+### **7.15 Reliability/availability**
+
+To provide the greatest utility, emergency telecommunications need to be both reliable and available. Whenever possible, admission control or network policy can increase the probability of successful telecommunications by providing a preferential treatment to emergency telecommunications.
+
+All components that encompass hardware, software and other resources of telecommunications should perform consistently and precisely according to their design requirements and specifications, and should be usable with high confidence – in accordance with service level agreements (SLAs).
+
+SLAs may assist in giving the ETS customer confidence that design requirements and specifications have been adhered to within the service provider's network.
+
+TeleManagement Forum's (TMF's) SLA Management Handbook [b-TMF GB917] specifies a formal methodology that may be used to develop SLAs between customers and service providers. The Handbook utilizes the concept of service level specification (SLS) to identify measurable parameters for inclusion with an SLA. The SLS is used to define key quality indicator (KQI) parameters, along with associated threshold values, for inclusion within an SLA. The use of SLA templates such as those specified by [ITU-T M.3342] is also recommended.
+
+Within TMF's SLA Handbook, development of an SLA specification is considered to be a "business process". This business process is further decomposed into lower level business processes that include:
+
+- capturing SLA requirements;
+- preparing draft SLA;
+- checking SLA completeness;
+- validating SLA specification;
+- signing-off SLA specification.
+
+The use of each business process is explained in detail from both a customer and a service provider perspective. Examples (referred to as 'use cases') showing how these business processes may be applied in the context of specific services (e.g., ETS) are also included.
+
+More in-depth examples, referred to as "application notes", are typically produced as separate documents. For example, [b-TMF GB934] is an application note dedicated to voice over IP SLA management. [b-TMF GB934] also includes a discussion of SLA management for voice over IP in
+
+the context of ETS. One of the key distinctions for ETS, as compared to publicly available services, is the emphasis on KQIs under abnormal (e.g., overload) conditions.
+
+In order to address network availability and reliability requirements, the ETS examples found in [b-TMF GB917] and [b-TMF GB934] may be used, particularly the discussion of voice service aspects found in [b-TMF GB934]. Additional ETS-specific SLA management work, which could address development for data and video KQIs, is for further study.
+
+### **7.16 ETS use of cloud infrastructure**
+
+[ITU-T Y.3501] provides general cloud computing requirements and capabilities. Annex A of this Recommendation contains the list of emergency telecommunications functional requirements and capabilities. Support for these requirements is needed when emergency telecommunications including ETS is offered by the cloud service provider (CSP) [ITU-T Y.3510].
+
+The cloud computing infrastructure that is currently being defined may be used by service providers (e.g., NGN providers) to support public network services such as emergency telecommunications including ETS. If the cloud computing infrastructure is used to support emergency telecommunications including ETS, the network resources and core transport network requirements for priority treatment as specified in this Recommendation are applicable, and would need to be accommodated. For example, ETS provides priority telecommunications to the ETS authorized users in times of disaster and emergencies. In the context of cloud resource management, if the cloud infrastructure is used to support public network services, authorized ETS users should be able to obtain priority access (i.e., preferential treatment) to the cloud resources. In addition, the emergency telecommunications requirements as specified in this Recommendation apply across multiple layers of the cloud reference architecture defined in [ITU-T Y.3501] and [ITU-T Y.3510].
+
+[ITU-T Y.3520] provides an overview of general concepts of end-to-end cloud computing resource management requirements. If cloud computing resources are used to support ETS, according to [ITU-T Y.3520] appropriate resource management functions will be needed to allow priority treatment in the use of cloud computing resources by authorized users.
+
+Appendix IV of [ITU-T Y.3510] provides some guidance and details on ETS use of cloud infrastructure resources relevant to both network resources and core transport network requirements specified in this Recommendation.
+
+## Annex A
+
+### A possible distinction between essential and optional requirements
+
+(This annex forms an integral part of this Recommendation.)
+
+| <b>Emergency telecommunications functional requirements and capabilities</b> | <b>Description</b>                                                                                                                                                                               | <b>Essential</b> | <b>Optional</b> |
+|------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|-----------------|
+| Enhanced priority treatment                                                  | Emergency traffic needs assured capabilities regardless of the networks traversed.                                                                                                               | X                |                 |
+| Secure networks                                                              | Networks should have protection against corruption of, or unauthorized access to, traffic and control (fraud), including expanded encryption techniques and user authentication, as appropriate. | X                |                 |
+| Location confidentiality                                                     | A limited number of high level leadership emergency telecommunication users may need to be able to use emergency telecommunications without risk of being located.                               |                  | X               |
+| Restorability                                                                | Certain network functionalities should be capable of being reprovisioned, repaired, or restored to required levels on a priority basis.                                                          |                  | X               |
+| Network connectivity                                                         | Networks supporting emergency telecommunications should provide international connectivity when possible, e.g., when [ITU-T E.106] and/or [ITU-T E.107] is applicable.                           | X                |                 |
+| Interoperability                                                             | Provide interconnection and Interoperability among all networks (evolving or existing).                                                                                                          | X                |                 |
+| Mobility                                                                     | The telecommunications infrastructure should support user and terminal mobility including re-deployable, or fully mobile telecommunications.                                                     | X                |                 |
+| Ubiquitous coverage                                                          | Public telecommunication infrastructure resources over large geographic areas should form the framework for ubiquitous coverage of emergency telecommunications.                                 | X                |                 |
+| Survivability/endurability                                                   | Capabilities should be robust to support surviving users under a broad range of circumstances.                                                                                                   | X                |                 |
+| Voice transmission                                                           | Circuit-switched and packet-switched networks should provide voice-band quality service for emergency telecommunications users.                                                                  | X                |                 |
+| Video transmission                                                           | Circuit-switched and packet-switched networks should provide Quality of Service with low packet error rate and loss for emergency telecommunications users.                                      | X                |                 |
+| Data transmission                                                            | Packet-switched networks should provide Quality of Service with low packet error rate for emergency telecommunications users.                                                                    | X                |                 |
+
+| <b>Emergency telecommunications functional requirements and capabilities</b> | <b>Description</b>                                                                                                                                                 | <b>Essential</b> | <b>Optional</b> |
+|------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------|-----------------|
+| Scaleable bandwidth                                                          | Authorized users should be able to select the capabilities of emergency telecommunications to support variable bandwidth requirements.                             |                  | X               |
+| Reliability/availability                                                     | Telecommunications should perform consistently and precisely according to their design requirements and specifications, and should be usable with high confidence. | X                |                 |
+| Preferential treatment in congestion control mechanisms                      | Congestion control mechanisms should support reduced measures for emergency telecommunications traffic compared to normal traffic.                                 |                  | X               |
+
+## Appendix I
+
+## Information on possible sources of disasters
+
+(This appendix does not form an integral part of this Recommendation.)
+
+Two types of forces produce most natural disaster events. These are: extreme weather conditions (storms), and earthquakes. Both can dissipate variable amounts of energy and produce different damage over various geographic areas. The hurricane (sometimes referred to as a typhoon or cyclone) generally covers wide geographic areas and is the most devastating extreme weather storm condition on earth. The wind, rain, and secondary effects such as floods from this type of storm often cause widespread and lasting damage to properties and people. Although many aspects (such as intensity and paths) of storms are somewhat predictable and can provide precious warning times to people, damage to properties and land still occurs. In contrast to extreme weather conditions, earthquakes are largely unpredictable, but confined to smaller geographic areas. Nevertheless, powerful forces of nature are still unleashed and significant damage to properties and people often occur, especially in densely populated areas of the world.
+
+Typically, natural disasters often set off additional clamorous events. For example, a hurricane may induce flash floods and mudslides. Hurricanes may cause rivers to overflow resulting in the death of livestock or damaged crops. People can be left without electricity or homes leaving them in need of food, clothing and shelter. Earthquakes continue to create damage after the initial quake through aftershocks. Sometimes earthquakes induce tidal waves that inflict additional damage to an already affected area. As seen in the recent past, some of these disasters may cascade and challenge the various measures planned to address them. An earthquake may set off effects in a nuclear facility, for example, and a chain of events that may not have been contemplated or considered when planning the response measures.
+
+Some natural disasters are presented in Table I.1.
+
+**Table I.1 – Natural disasters**
+
+|                                |
+|--------------------------------|
+| Avalanches                     |
+| Drought                        |
+| Earthquakes                    |
+| Epidemics                      |
+| Flash floods                   |
+| Famine                         |
+| Floods                         |
+| Forest fires                   |
+| Lightning                      |
+| Hurricanes                     |
+| Mudslides                      |
+| Severe cold, snow, ice or heat |
+| Tidal waves                    |
+| Tornados                       |
+| Tsunamis                       |
+| Typhoons                       |
+| Volcano eruptions              |
+| Wind storms                    |
+
+Disaster events that stem from human sources can also vary in energy, geographic distribution, duration, and damage potential.
+
+Human caused disasters can rival those of nature. As with natural disasters, there may be additional ramifications stemming from the initial event. For example, a fire in a coal-mine can result in loss of life from burns or smoke inhalation. Such fires may trap people inside the coal-mine and lead to other explosions. A list of disasters caused by humans can be found in Table I.2.
+
+**Table I.2 – Man-made disasters**
+
+|                                               |
+|-----------------------------------------------|
+| Arson                                         |
+| Chemical spills                               |
+| Collapse of industrial or domestic structures |
+| Explosions                                    |
+| Fires                                         |
+| Gas leaks                                     |
+| Nuclear explosions                            |
+| Pipeline ruptures                             |
+| Plane crashes/emergency landings              |
+| Poisoning                                     |
+| Radiation                                     |
+| Ships sinking/colliding                       |
+| Stampedes                                     |
+| Subway collisions/derailments                 |
+| Terrorism                                     |
+| Train collisions/derailments                  |
+| Water-borne accidents                         |
+
+## Bibliography
+
+- [b-IETF RFC 5559] IETF RFC 5559 (2009), *Pre-Congestion Notification (PCN) Architecture*.
+- [b-IETF RFC 6409] IETF RFC 6409 (2011), *Message Submission for Mail*.
+- [b-Nichols] Nichols, K., Jacobson, V. (2012) *Controlling Queue Delay*. Association for Computer Machinery.  
+<<http://queue.acm.org/detail.cfm?id=2209336>>
+- [b-TMF GB917] TMF GB917 (04/2012), *SLA Management Handbook Release 3.1*.
+- [b-TMF GB934] TMF GB934 (06/2008), *Application Note to SLA Management Handbook, Release 2.0*.
+
+
+
+
+
+# SERIES OF ITU-T RECOMMENDATIONS
+
+|                 |                                                                                                  |
+|-----------------|--------------------------------------------------------------------------------------------------|
+| Series A        | Organization of the work of ITU-T                                                                |
+| Series D        | General tariff principles                                                                        |
+| Series E        | Overall network operation, telephone service, service operation and human factors                |
+| Series F        | Non-telephone telecommunication services                                                         |
+| Series G        | Transmission systems and media, digital systems and networks                                     |
+| Series H        | Audiovisual and multimedia systems                                                               |
+| Series I        | Integrated services digital network                                                              |
+| Series J        | Cable networks and transmission of television, sound programme and other multimedia signals      |
+| Series K        | Protection against interference                                                                  |
+| Series L        | Construction, installation and protection of cables and other elements of outside plant          |
+| Series M        | Telecommunication management, including TMN and network maintenance                              |
+| Series N        | Maintenance: international sound programme and television transmission circuits                  |
+| Series O        | Specifications of measuring equipment                                                            |
+| Series P        | Terminals and subjective and objective assessment methods                                        |
+| Series Q        | Switching and signalling                                                                         |
+| Series R        | Telegraph transmission                                                                           |
+| Series S        | Telegraph services terminal equipment                                                            |
+| Series T        | Terminals for telematic services                                                                 |
+| Series U        | Telegraph switching                                                                              |
+| Series V        | Data communication over the telephone network                                                    |
+| Series X        | Data networks, open system communications and security                                           |
+| <b>Series Y</b> | <b>Global information infrastructure, Internet protocol aspects and next-generation networks</b> |
+| Series Z        | Languages and general software aspects for telecommunication systems                             |