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6594210c8e581b7f1789ecc511da8c78 | 101 308 | 4 Operating modes | H.323 and SIP have a number of declared modes of operation that relate the various functions they identify and define how calls are routed and controlled within their environment. The following clauses identify each mode of operation that is relevant to a potential network context requiring interworking from one protocol technology to another. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 4.1 Native H.323 operating modes | H.323 is an architecture for implementing multimedia conferencing over a packet network. It comprises application-layer control protocols that can establish, modify and terminate multimedia sessions or calls. These multimedia sessions may include multimedia conferences, distance learning, Internet telephony and similar applications. It has essentially three possible modes of operation relevant to possible interworking requirements in the context of TIPHON networks. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 4.1.1 H.323 peer-to-peer mode | H.323 supports a peer-to-peer mode of operation. In a peer-to-peer architecture, endpoints contact each other directly, without any control or co-ordination from any gatekeeper or intermediate server. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 4.1.2 H.323 gatekeeper routed call signalling mode | A gatekeeper may play an active role in mediating call signalling between the calling and called end-points in H.323 networks with gatekeepers. In this environment, a gatekeeper may not only assume responsibility for call routing and authorization on behalf of served endpoints but may also act as the signalling endpoint for calls entering an administrative domain. ETSI ETSI TR 101 308 V1.1.1 (2001-12) 8 |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 4.1.3 H.323 direct call signalling mode | The strict peer-to-peer and gatekeeper routed models may be combined into a hybrid approach referred to as Direct Call Signalling. In this case, gatekeepers provide call routing and authorization while individual endpoints are responsible for establishing and disconnecting calls and media streams directly between each other. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 4.1.4 H.323 registration | An H.323 zone is the collection of all terminals, gateways, and Multipoint Control Units managed by a single gatekeeper. Registration is the process by which an endpoint joins an H.323 zone and informs the gatekeeper of its transport and alias addresses. Once established, the registration of an end-point with a specific gatekeeper may need to be refreshed on a periodic basis. An end-point must register with a gatekeeper before it can accept any call attempts. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 4.2 Native SIP operating modes | As defined in RFC 2543 [2], the Session Initiation Protocol (SIP) is an application-layer control protocol that can establish, modify and terminate multimedia sessions or calls. These multimedia sessions may include multimedia conferences, distance learning, Internet telephony and similar applications. The most common SIP operation is the invitation. Instead of directly reaching the intended destination, a SIP request may be redirected by Redirect Server or proxied through Proxy Server. Users can also register their location(s) with SIP Registrar. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 4.2.1 SIP peer-to-peer | In a peer-to-peer architecture, User Agents (UA) contact each other by sending invitation directly, without any control or co-ordination from any proxy. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 4.2.2 SIP proxy routed | SIP messages may be routed via an intermediary known as a proxy server. In such an environment, proxies not only assume responsibility for call routing and authorization on behalf of their endpoints, they may also act as the signalling endpoint for calls into their administrative domain. A proxy server can either be stateful or stateless. A stateful proxy retains state information concerning both an incoming request and any associated outgoing requests. In contrast, a stateless proxy does not retain any information concerning a received message or its response once an outgoing request has been generated. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 4.2.3 SIP with redirect server | SIP redirect servers represent an example of a loosely coupled distributed architecture. In this environment, the redirect server provides the call routing information such that the originating UA first establishes a signalling connection with the redirect server, before being re-directed to the terminating UA. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 4.2.4 SIP registration | The SIP REGISTER method allows a client to let a SIP Registrar know at which address or addresses it can be reached. A client may also use it to install call handling features at the server. A SIP Registrar may be collocated with either a proxy or redirect server. ETSI ETSI TR 101 308 V1.1.1 (2001-12) 9 |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 4.3 Recommended modes of operation | |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 4.3.1 H.323 administrative domain | H.323 Gatekeeper H.323 Terminal H.323 H.323 Terminal H.323 Terminal Figure 1: An H.323 administrative domain While a gatekeeper is an optional element for an H.323 network, it is recommended that TIPHON based H.323 centric networks are deployed with an H.323 Gatekeeper. This should be configured to require registration with all the end points within its administrative domain. It is further recommended that Gatekeeper Routed Call Signalling is used in preference to Direct Call Signalling in order to support enhanced calling features such as availability look-ahead for the called terminal. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 4.3.2 SIP administrative domain | As defined in RFC 2543 [2], SIP has no concept of an Administrative Domain. However for practical network engineering and operational reasons consistent with the TIPHON approach to QoS [3], the cocept of a SIP Administrative Domain is introduced. This enables the trust boundaries within which all SIP devices are controlled by a single operator to be delineated. Each SIP Administrative Domain is assumed to contain at least one Registrar. All SIP UAs within that domain must register with the Registrar in order to allow the user's or terminal's address(es) to be advertised within the domain. SIP Registrar SIP UA SIP SIP UA SIP UA Figure 2: A SIP administrative domain ETSI ETSI TR 101 308 V1.1.1 (2001-12) 10 |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 5 Interworking scenarios | Since the information elements and elements of procedure offered by both SIP and H.323 are capable of supporting a wide range of services and applications, connecting a SIP network and H.323 network together will be more or less complex to achieve depending upon the services being supported in a given scenario. To enable interworking between two such networks to occur reliably, it is necessary to identify the core the conditions and events that will typically be involved. The scenarios below are examples defined to facilitate the identification of such conditions and events. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 5.1 Simple scenarios | |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 5.1.1 Dual Stacking in endpoints | The simplest approach to achieving interworking between SIP and H.323 is to provide access to both protocol stacks within the same endpoint. However, while this will provide the means where calls can be originated and terminated from both types of network, it leaves any additional interworking issues to the responsibility of terminal equipment manufacturer and will be inherently non-standard. It is therefore not seen as a long term solution. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 5.1.2 Interworking between a SIP domain and an H.323 domain | SIP H.323 I W F SIP Endpoint H.323 Endpoint Figure 3: Interworking scenario - between a SIP domain and an H.323 domain The alternative to providing access to both H.323 and SIP protocols within the same end-point requires the provision of a suitable Interworking Function (IWF) that allows a call originated using one protocol to be terminated using the other. This will necessitate the messages provided by SIP and H.323 to be related through a mapping process within the IWF. Message mapping between protocols may be achieved on either a state-full or state-less basis and will require careful attention depending upon the overall information flows required. However, before any such call flows can be provided, it will be necessary for the end-points to be able to addressable outside of their native protocol domain. This will have to be achieved in association with some form of registration process or procedure. Registration may be made from one domain to the other depending on the arrangement of the Administration Domains concerned as discussed further in clause 5.4. ETSI ETSI TR 101 308 V1.1.1 (2001-12) 11 |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 5.2 Practical interworking scenarios | 5.2.1 Interconnection between 3GPP SIP based network and TIPHON H.323 Network GGSN 3GPP Network TIPHON Network SGSN CSCF (SIP Server) Mm Gi SIP-MT H.323 I W F SIP Media Gateway Media Gateway Figure 4: Interconnection between TIPHON and 3GPP Network TIPHON envisages a future network environment where all types of network - whether fixed, mobile, or satellite - are combined in a manner permitting users to access services regardless of their terminal type, network connection or geographical location. 3GPP have developed a SIP based mobile network architecture for third generation mobile networks as part of the 3GPP Release 5 activities. This identifies a multimedia network interface (Mm in figure 4) that could be realized by a TIPHON compliant fixed network. The TIPHON vision of a fully IP based network interworking with existing fixed and mobile networks therefore complements the 3GPP Release 5 all-IP network vision. Where the TIPHON network connecting with the 3GPP network is based upon H.323, there would be the need to establish interworking between SIP and H.323 across the interface between the two networks, as indicated in figure 4. ETSI ETSI TR 101 308 V1.1.1 (2001-12) 12 |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 5.2.2 Interconnecting PacketCable and TIPHON H.323 Networks | PacketCable Network TIPHON System Call Management System (CMS) SIP H.323 I W F SIP Media Gateway Media Gateway Media Terminal Adapter (MTA) RTP NCS Figure 5: Interconnection between TIPHON and PacketCable Network PacketCable™ is a project conducted by Cable Television Laboratories, Inc. (CableLabs®) and its member companies. The PacketCable project is aimed at defining interface specifications that can be used to develop interoperable equipment capable of providing packet-based voice, video and other high-speed multimedia services over Hybrid Fibre Coax (HFC) cable systems based upon the DOCSIS protocol. PacketCable consists of a variety of functional components, to create a mechanism for packet-based services. These include the: - Multimedia Terminal Adapter (MTA) which is a PacketCable client device that contains a subscriber-side interface to the subscriber's CPE (e.g. telephone) and a network-side signalling interface to call control elements in the network. An MTA provides codecs and all signalling and encapsulation functions required for media transport and call signalling; - Call Management Server (CMS) which provides call control and signalling related services for the MTA, Cable Modem Termination System (CMTS), and PSTN gateways in the PacketCable network. The CMS is a trusted network element that resides on the managed IP portion of the PacketCable network. The CMTS provides connectivity between the DOCSIS HFC Access Network and a Managed IP Network; - Cable Modem Termination System (CMTS) which provides data connectivity and complimentary functionality to cable modems over the HFC access network. It also provides connectivity to wide area networks. The CMTS is located at the cable television system head-end or distribution hub. As shown in figure 5, PacketCable are currently developing a SIP based interface for use between CMS functions. As this solution is deployed, there will be the opportunity to connect with networks of different types that may include H.323 based networks, or networks based upon other network protocols. As an illustration of possible future options, figure 5 depicts a scenario demonstrating a PacketCable network being connected with an H.323 based TIPHON network. ETSI ETSI TR 101 308 V1.1.1 (2001-12) 13 |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 5.3 Tandem scenarios | |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 5.3.1 Tandem connection of H.323 domains via a SIP intermediary | H.323 H.323 I W F SIP I W F H.323 Endpoint H.323 Endpoint Figure 6: Interworking Scenario - H.323 domains Tandem through a SIP domain As H.323 and SIP networks become increasingly deployed, it is likely that a call could originate from an H.323 network, be subsequently transported via an intermediate network based upon SIP and then terminate on a H.323 device via a second point of interworking. Ideally in such a case, H.323 messages would be terminated by the Interworking Function (IWF) at the originating H.323-to-SIP boundary with the message semantics being conveyed across the SIP domain using native SIP messages. The reverse operation would ideally be performed by the IWF at the SIP-to-H.323 boundary. However it is currently unlikely that the messages supported by H.323 and SIP can be exactly mapped. In addition, as both protocols increasingly support mechanisms to transport protocols such as DSS.1 by encapsulation, there is the added complication that the IWF may be presented with embedded information elements relating to neither H.323 nor SIP. Furthermore, tunnelling may be necessary to support end-to-end H.323 services that are not supported by the SIP domain. Other aspects of protocol tunnelling are discussed further in clause 6.2. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 5.3.2 Tandem connection of SIP domains via an H.323 intermediary | SIP SIP I W F H.323 I W F SIP Endpoint SIP Endpoint Figure 7: Interworking Scenario - SIP domains Tandem through an H.323 domain An analogous situation to that described in clause 5.3.1 applies in the case where two SIP devices are interconnected through an intermediate H.323 based network. In this case, the SIP messages would usually be terminated by the IWF at the SIP-to-H.323 boundary and their semantics conveyed across the H.323 domain using native H.323 messages where it is possible to do so. The reverse operation needs to be performed by the IWF at the H.323-to-SIP boundary to produce the terminating call segment. As with the case described in clause 5.3.1, there is the potential scenario where protocols other than SIP may be transported in an encapsulated form. This scenario is discussed further in clause 6.2. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 5.4 Support of administrative domains | The registration of end-points with intermediary server elements forms an essential feature of any large scale VoIP technology since without these elements, only a simple strictly peer-to-peer solution can be supported. There are three options for arranging such administrative control as discussed in the following clauses. ETSI ETSI TR 101 308 V1.1.1 (2001-12) 14 |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 5.4.1 Administrative control from a SIP domain | H.323 Terminal H.323 H.323 Terminal I W F SIP Registrar SIP UA SIP SIP UA Figure 8: An IWF between SIP and H.323 within a SIP Administrative Domain In this case, it is assumed that the SIP and H.323 networks fall under the control of the same administration and that the H.323 network is effectively considered to be sub-servant to the SIP network. The SIP Registrar within the administrative domain therefore provides the registration function for all end points within domain irrespective of the protocol type employed. The IWF and all H.323 terminals are therefore under the control of this SIP Registrar. To make this realisable from a practical point of view, the IWF will have to support a method of registering an H.323 end-point with a SIP registrar. This will need to support procedures that allow device discovery, end-point registration and de-registration in an appropriately secured manner. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 5.4.2 Administrative control from an H.323 domain | H.323 Gatekeeper H.323 Terminal H.323 H.323 Terminal I W F SIP UA SIP SIP UA Figure 9: An IWF between SIP and H.323 within an H.323 Administrative Domain In this case, the administrative control is provided by an H.323 based network with a Gatekeeper. Within the administrative domain all end-points must be registered with the Gatekeeper and the IWF and all SIP UA are therefore under its administrative control. This requires that the IWF needs to support methods of device discovery and registering and de-registering a SIP UA with an H.323 gatekeeper. ETSI ETSI TR 101 308 V1.1.1 (2001-12) 15 |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 5.4.3 Interworking between administrative domains | H.323 Gatekeeper H.323 Terminal H.323 H.323 Terminal I W F SIP Registrar SIP UA SIP SIP UA Figure 10: An IWF between SIP and H.323 among separate administrative domains In this case, the SIP domain and the H.323 domain are controlled by separate and independent administrative domains with equal administrative status. The IWF may be administered within the SIP domain, the H.323 domain or an entirely separate domain administered by a third party. The explicit registration of individual end points across the boundary between the two domains may or may not be necessary depending on the arrangements between the domains concerned and the trust relationship between them. The identification and location of a user across the domain boundary needs to be supported by inter-domain protocols, procedures or processes as appropriate. This gives rise to two possible relationships concerning the actual interconnection between the two domains; a direct peering relationship and an in-direct peering relationship. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 5.4.3.1 Direct peering | A direct peering relationship occurs where two administrative domains interwork without reliance on any intermediate third party. The signalling route and the required protocol are therefore known and agreed a-priori by the two administrative domains concerned. The SIP side of the IWF therefore belongs to the SIP administrative domain and the H.323 side of the IWF belongs to the H.323 administrative domain. The IWF registers its SIP interface to the SIP Registrar, and its H.323 interface to the H.323 Gatekeeper. Depending on the construction of the IWF, there may be a separate interworking interface exposed between the SIP side and H.323 side of the IWF. This may use either protocol configured in an inter-domain form or an entirely separate third protocol. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 5.4.3.2 In-direct peering | With the in-direct peering scenario, neither domain has a-priori knowledge of the arrangement concerning the origination and termination route for any given call. The IWF is under the administrative control of a single domain that may be a SIP, H.323 or a protocol domain based on an alternative technology. A third party, such as a Clearinghouse server, is required to identify the destination of each call and possibly invoke an IWF if required. The administrative domain that controls the IWF may be the origination of the call, the termination of a call, or an independent third party. In-direct peering is not limited to calls that require charging facilities so information about the destination may be obtained by simple mean such as DNS where more complex features are not required. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 6 Encapsulation of other signalling protocols | H.323 and SIP both have the capability to support the encapsulation and transport of signalling information elements associated with other signalling protocols. This is also known as tunnelling. Where an H.323 network interfaces with a SIP based network and either one implements tunnelling of other protocols, the handling of the tunnelled protocol at the interface between the two networks needs to be determined. This clause identifies a number of scenarios where this may occur and indicates the areas that need to be considered further. ETSI ETSI TR 101 308 V1.1.1 (2001-12) 16 |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 6.1 Control of tunnels through IWF | The existence of a tunnel within a signalling stream and its handling at an IWF is an essential aspect of inter-domain interworking. Depending upon the specific context, it may be necessary to be able to identify a specific tunnel, determine the nature of the encapsulated information and be able to control whether the tunnel is allowed and active or prevented, depending upon some external policy applied at the IWF. Whether a tunnel will be allowed or not may be determined on a per call basis depending on the administrative policy within the terminating domain. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 6.2 Encapsulation of native signalling | There are two cases of particular interest when considering the interconnection of SIP and H.323 networks from the point of view of the transport of encapsulated signalling that extend the scenarios described in clauses 5.3.1 and 5.3.2. In the first scenario which is shown in figure 11, a SIP network acts as the intermediary between an originating H.323 network and a terminating H.323 network and. To allow a fuller feature set to be supported between the H.32 end-points, there is the need to establish an H.323 protocol tunnel across the SIP network that allows the full H.323 protocol to be exposed between the end-points without exposing the overall routing across the intermediate SIP domain. H.323 H.323 SIP I W F I W F (2) (1) Figure 11: H.323 Tunnel Through SIP The second scenario, shown in figure 12, an H.323 based network acts as the intermediary between two SIP networks. In this case, the simple mapping of protocol information elements described in clause 5.3.2 will prevent a richer set of SIP functionality to be exposed at the originating and terminating end-points. A protocol tunnel is therefore required that, under the control of the intermediate H.323 domain, can transport SIP information elements. (4) (3) SIP SIP H.323 I W F I W F Figure 12: SIP Tunnels Through H.323 In either of the cases considered in this clause, there is the need to provide management and control of the protocol tunnels to ensure that external administrative policies are not being circumvented. ETSI ETSI TR 101 308 V1.1.1 (2001-12) 17 |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 6.3 Encapsulation of other signalling | This clause considers the case where either SIP or H.323 are transporting foreign signalling system such a Q.SIG or ISUP. There are essentially two core scenarios to be considered depending on whether a SIP or H.323 based network constitutes the intermediate domain. H.323 H.323 SIP I W F I W F S G S G (2) (3) (4) (5) (1) Figure 13: Tunnelling Scenarios - "H.323 Tandem Through SIP" Figure 13 depicts the set of scenarios where a SIP network acts as the intermediary between an originating H.323 network and a terminating H.323 network. This exposes a number of sub-cases depending upon the arrangements of non-native signalling and the ability of H.323 and SIP to handle tunnels. ETSI ETSI TR 101 308 V1.1.1 (2001-12) 18 SIP SIP H.323 I W F I W F S G S G (7) (8) (9) (10) (6) Figure 14: Tunnelling Scenarios - "SIP Tandem Through H.323" An alternative arrangement is possible where an H.323 network forms the intermediary. This scenario is shown in figure 14. From both of these examples, the following generic are identified depending upon the behaviour required from either H.323 or SIP with respect to the management of protocol tunnels: - Cases 1 and 6 - both SIP and H.323 support the semantics of the end-to-end signalling message and require no tunnelling. - Cases 2 and 8 - H.323 supports the semantics of the end-to-end signalling message but SIP does not. A tunnel is therefore required through the SIP domain only. - Cases 3 and 7 - SIP supports the semantics of the end-to-end signalling message but H.323 does not. A tunnel is therefore required through the H.323 domain only. - Cases 4 and 9 - neither SIP nor H.323 support the semantics of the end-to-end signalling message. However, an IWF has a method to convert the tunnelled information between SIP and H.323. The tunnelled message is extracted at the IWF and re-encapsulated with the tunnelling method of the other protocol. - Cases 5 and 10 - neither SIP nor H.323 support the semantics of the end-to-end signalling message. The IWF does not have a method to convert the tunnelling method between SIP and H.323. Therefore, the tunnel message has to be double encapsulated to pass through the concatenation of networks. ETSI ETSI TR 101 308 V1.1.1 (2001-12) 19 |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 7 Other considerations | |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 7.1 Security considerations | There are two distinct roles for IWFs depending on whether they are used to interconnect networks within a single administrative domain or form an interconnection between networks under the control of separate administrative policies. In particular; - An intra-domain IWF need not be concerned with security to any degree other than that required for normal end-to-end operation. - An inter-domain IWF, is positioned between administrative domains. It must by nature act as the final arbitrator between administrative domains. This implies that the IWF must be a trusted entity. In order to properly establish and maintain this trust, the IWF must have appropriate credentials. An inter-domain IWF must therefore address: - Authenticated Administrative Access - at least requiring a password, permitting password changes, and preventing the use of "bad" passwords. Mechanisms stronger than passwords (one-time tokens, etc) are recommended and should be supported. - Multi-level Administrative Access - at least an operator view without the ability to change IWF configuration and an administrator view which does have the ability to change configuration. Each view should have its own authentication tokens (passwords, etc). - Access Control Rules - to permit or disallow call setup requests from individual IP addresses as well as ranges of them. - Detailed Logging to Persistent Storage - support for logging to one or more remote storage locations should be provided. This log should include administrator accesses, detailed descriptions of configuration changes by administrators, as well as some call-by-call detail logging. Settable logging levels should be provided, to allow either more or less detail than the default to be logged. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 7.1.1 Signalling security | In inter-domain IWF should provide support for all standard authentication, privacy and other security methods relating to H.323 and SIP, as these are defined. An IWF intended for intra-domain use need not support security mechanisms. For cases involving tunnelling, the IWF should provide the ability to use both security mechanisms. For example, when tunnelling H.235-secure messages over SIP, the IWF should provide the ability to use IPSEC and/or any native-SIP authentication or other security mechanisms to secure the tunnelling messages. This allows administrative transparency. An H.323 signalling network may treat a SIP leg as "just another leg", while the operator of the SIP network may elect to provide this service over a public network, unbeknown to the H.323 network's operator, and do so securely with strong encryption. This allows the security considerations of the network using the tunnel to be clearly separated from the security considerations of the network providing the tunnel. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 7.1.2 Media security | An IWF intended for intra-domain interworking may optionally provide mechanisms providing media security. An IWF intended for inter-domain interworking should be aware of media security mechanisms by supporting - access control lists (e.g. firewall functionality); - differences in addressing policy (e.g. network address translation); - packet level security (e.g. IPSEC). ETSI ETSI TR 101 308 V1.1.1 (2001-12) 20 |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 7.2 Addressing and naming consideration | Applications such as emergency calling require specific location address information to be passed from the originating domain to the terminating domain. Where H.323 domains and SIP domains are connected together, it is important that such information be made available to the terminating side. In addition, it is important that address information received by the terminating side of the IWF is sufficient for the called party to be able to return a call to the calling party if so required. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 7.3 Quality of service considerations | Interworking between H.323 and SIP at the signalling level may have implications for QoS mechanisms used to provide QoS for both the signalling and media within each domain. This remains for further study. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 7.4 Management considerations | |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 7.4.1 Reporting | The IWF should support configuration and status reporting of its service, network and security parameters. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 7.4.2 Diagnostic test | The IWF should allow service and network element tests from authorized and authenticated administrative personnel. This should include self-diagnostic tests. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 7.4.3 Fault management | The IWF should provide functionality that enables fault management processes to allow the detection and isolation of abnormal conditions affecting its operation. |
6594210c8e581b7f1789ecc511da8c78 | 101 308 | 8 Prioritized requirements | For the purposes of TIPHON, a Simple Call Service Application shall support the following scenarios: • Interworking between a SIP domain and an H.323 domain; • Administrative Control from a SIP Domain; • Administrative Control from an H.323 Domain; • Interworking between Administrative Domains with In-direct Peering; • Interworking between Administrative Domains with Direct Peering; • Control of Tunnels through an IWF. ETSI ETSI TR 101 308 V1.1.1 (2001-12) 21 Annex A: Bibliography - ITU-T Recommendation H.245: "Control protocol for multimedia communication". - ETSI TR 101 300: "Telecommunications and Internet Protocol Harmonization Over Networks (TIPHON); Description of Technical Issues". - ETSI TS 101 321: "Telecommunications and Internet Protocol Harmonization Over Networks (TIPHON); Open Settlement Protocol (OSP) for Inter-Domain pricing, authorization, and usage exchange". - ITU-T Recommendation H.235: "Security and encryption for H-Series (H.323 and other H.245-based) multimedia terminals". - RFC 2401 (1998): "Security Architecture for the Internet Protocol". - IMTC aHIT!: "Interoperability Requirements for SIP and H.323 Interworking", March 2000. - SIP-H.323 Interworking Requirements: "draft-agrawal-sip-h323-interworking-reqs-00.txt", Argrawal, et al, July 2000. - Interworking Between SIP/DSP and H.323: "draft-singh-sip-h323-01.txt", Singh and Schulzrinne, May 2000. - 3GPP TS 24.229: "3rd Generation Partnership Project; Technical Specification Group Core Network; IP Multimedia Call Control Protocol based on SIP and SDP; stage 3 (Release 5)". - PacketCable CMS to CMS Signalling Specification, PKT-SP-CMSS-D01-001010, October 2000. ETSI ETSI TR 101 308 V1.1.1 (2001-12) 22 History Document history V1.1.1 December 2001 Publication |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 1 Scope | The present document describes an example of the ISI requirements that are needed to connect public safety systems together. The example describes the result of the pilot between the Netherlands, Belgium and Germany. NOTE: At the moment of writing Germany has not made a decision about their digital radio network. The requirements cover the following functionality: • Requirements for SwMI and mobile configuration prior to user migration across ISI. • Characteristics of services available to migrating users. • Characteristics of services available when calling users or groups in international cooperation. The present document does not describe the technical solution to the ISI. The focus of the present document is a solution where a fixed network topology as described in clause 6 is implemented. Future enhancements, although possible, are not described here. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 2 References | For the purposes of this Technical Report (TR), the following references apply: [1] TETRA MoU: "Functional requirements for the TETRA ISI Derived from Three-Country Pilot Scenarios". |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 3 Definitions and abbreviations | |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 3.1 Definitions | For the purposes of the present document, the following term and definition applies: Three-Country Pilot scenario: operational scenarios derived from international interoperability discussions between Belgium, Netherlands and Germany |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 3.2 Abbreviations | For the purposes of the present document, the following abbreviations apply: CCK Common Cipher Key DCK Derived Cipher Key DGNA Dynamic Group Number Assignment GCK Group Cipher Key IPI IP Interworking ISDN Integrated Services Digital Network ISI Inter-System Interface ISSI Individual Short Subscriber Identity KS Session Key (also KS" as alternative session key) MS Mobile Station MoU Memorandum of Understanding OTAR Over The Air Rekeying RS Random Seed SCK Static Cipher Key SDS Short Data Service SFPG Security and Fraud Prevention Group ETSI ETSI TR 101 448 V1.1.1 (2005-05) 7 SwMI Switching and Management Infrastructure TETRA TErrestrial Trunked RAdio TL Transport Layer TPI Talking Party Identity |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 4 General connection requirements | |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 4.1 ISI general topology | The ISI between Public safety networks in Europe could potentially use a number of connection topologies: 1) Mesh of permanently leased lines. 2) Transit switched network, such as Private ISDN Network. 3) Packet switched intervening network, such as an Intranet. 4) Mesh of connections to other SwMIs, where other SwMIs perform transit-switching functions. The second and third option require an intervening network, where the ownership, responsibilities and security details are not clear at this time. These options will therefore be discounted in this stage. The fourth option, transit switching, is considered insecure, and will also be discounted. Therefore the adopted option for connecting the networks of the Netherlands, Belgium and Germany will be the first, i.e. a leased line direct connection to each other SwMI where there is an ISI required. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 4.2 ISI bandwidth and points of connection | An ISI connection between two networks could consist of one or more sets of connections. A single connection to another SwMI is the simplest possible solution. Two or more geographically separate connections between pairs of SwMIs could allow resilience, and could also reduce traffic backhauling requirements in some circumstances. However it would introduce additional complexity, especially when visitors roam in the visited SwMI between points of connection of ISI. Therefore the connection between two SwMIs will be a single connection from a single interface point on one SwMI to a single interface point on the other SwMI. The bandwidth of the connection will depend on the expected traffic load. The current circuit switched ISI limits one traffic connection to 64 kbps; i.e. each inter system call requires a 64 kbps connection. The current assumption is that one E1 connection per connected network will be needed. It should be possible to increase the capacity of the connection. One E1 will support 30 simultaneous calls. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 4.3 ISI security | It is necessary to provide both authenticity and confidentiality on the ISI. This will ensure that the other SwMI cannot be impersonated. It will also ensure that the link, which by its nature will be crossing an international border, and may be carried by a non-specific medium, cannot be intercepted. The work to provide TETRA specific ISI security including SwMI authentication was not completed. The protection of the link will take place by the use of bulk encryption devices at both ends. The specification of these devices is outside the scope of the present document. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 4.4 ISI quantities | As an initial assumption, it will be assumed that a maximum 5 separate ISI connections will be required per SwMI. A full mesh will be used to connect SwMIs. When more than 5 SwMIs are to be interconnected, a different topology will be considered. ETSI ETSI TR 101 448 V1.1.1 (2005-05) 8 |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 4.5 ISI configuration | It will be necessary to configure each ISI connection independently, with details of the connected system, for example TETRA Mobile Network Code etc. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 4.6 ISI performance | |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 4.6.1 Call setup delay | Call setup delay is defined as the delay experienced by the transmitting party between pressing PTT and getting an audio indication for permission to talk. For multi-SwMI group calls the call setup delay should be less than 1,0 seconds for: • calls started in the group home SwMI • calls started in a participating SwMI. Conditions for measurement: • Permission to talk should only be signalled if resources are checked to be available on all involved basestations in all participating SwMI's. • The specified value is defined only for situations where there is good RF coverage and no queuing for ISI or basestation resources takes place. • Mobiles to be used for the measurement are from the same manufacturer as the local infrastructure. • 3 sites involved per infrastructure. • 95 % of the setups should be within the specified time. The evaluation of call-setup delay will be done by checking the time-difference between U-setup and D-connect-Ack in the basestation log (Measured value to be extended by 0,2 sec to represent the call setup delay experienced by the transmitting party). |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 4.6.2 Audio delay | The end-to-end audio delay experienced by the users for calls without end-to-end encryption over the ISI should not be higher than 0,7 seconds. A measurement method is to be agreed. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 4.6.3 Migration | The initial migration registration procedure (including authentication) to a foreign network should not take more than 1,0 seconds longer than the first registration (including authentication) on the home network of a radio. The evaluation of the migration registration performance will be done by checking the time-difference between U-location-update-demand and D-location- update-accept in the basestation log. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 5 Mobility management requirements | |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 5.1 Configuration of subscriber ids permitted to migrate | It is not considered safe for any subscriber claiming to originate from a connected SwMI to be allowed to migrate in without specific authorization. ETSI ETSI TR 101 448 V1.1.1 (2005-05) 9 It is not considered feasible to individually pre-provision each and every subscriber in each SwMI that a user may migrate to. This would create logistical problems, as it would be difficult to maintain an accurate database of all potential users from another system. Therefore the visited network first checks if the visiting user fulfils basic migration requirements. The purpose of this check is to be able to refuse unwanted foreign users to avoid unnecessary signalling over ISI. After this first, local check the home network of the subscriber is considered the main responsible party for providing up-to-date authorization for migration. This authorization is checked during authentication. • For the first, local check blocks of permitted subscribers should be provisioned in each SwMI for every connected SwMI. Whereas the functionality available to each subscriber whilst migrating will be defined in profiles, at the time of migration, the home SwMI should always be checked to ensure that the subscriber is permitted to migrate, and the subscriber should be authenticated based on security parameters obtained from the home system over the ISI. NOTE: A MS will only be allowed to migrate to a SwMI that is directly connected to its home SwMI. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 5.1.1 Pre-provisioning subscriber profiles | Local pre-defined migration profiles will be defined in connected SwMIs and migration profile exchange for subscribers over ISI is not supported. A pre-defined migration profile is supported in all connected SwMIs. Any migration request using a different pre-defined migration profile number will be rejected. This provisioning within a SwMI will include the following functionality: • Service/Feature availability for foreign subscribers. This should include: - Group call. - Individual call. - Telephone call. - Status. - SDS. - Packet data. The ISI Mobility Management standard does not define the contents of pre-defined migration profiles, therefore as a minimum the pre-defined migration profiles should be based on the mandatory parameters defined in the subscriber migration profile that can be sent over ISI. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 5.1.2 Migration approval upon registration request | When a visiting MS attempts to register on a foreign SwMI, the following steps should be taken: • The foreign SwMI may check that the identity of the migrated subscriber is within one of the permitted blocks of identities. • The (local) migration profile of the subscriber should be determined. • The foreign SwMI should communicate with the home SwMI of the migrated subscriber to confirm that the MS is permitted to migrate to a foreign network. • The authentication session key material should be received from the subscriber's home SwMI. • The foreign SwMI should authenticate the migrated subscriber based on the authentication session key material received. • Once migration has been successful the visited SwMI reports this to the home SwMI. Home SwMI and visited SwMI update their databases. ETSI ETSI TR 101 448 V1.1.1 (2005-05) 10 NOTE: Only when authentication has been approved will the migrated user be successfully registered to the foreign SwMI. If any of the steps above fail, the subscriber registration will be rejected. A migration request will always specify authentication being required, security parameters (RS, KS, KS' for use with authentication in the visited SwMI) will therefore always be received from the subscriber's home SwMI before migration acceptance is performed. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 5.1.3 Detachment | When the MS detaches from the foreign SwMI, the foreign SwMI should inform the home SwMI of the detachment, and should immediately delete its record of the MS, including session keys held for that MS. The Home SwMI should mark the MS as 'not migrated' in its database. If the MS attaches to its home SwMI, or to another foreign SwMI without detaching from the first visited SwMI, the home SwMI should inform the first visited SwMI that the MS is no longer migrated to that SwMI, and that first visited SwMI should delete its record of the MS, including session keys held for that MS. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 5.1.4 Restricted migration | Restricted migration is the ability for a SwMI to allow subscribers that have not been configured in the foreign SwMI to make and receive emergency calls. Restricted migration will not be supported in the networks due to the resulting security risk. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 5.1.5 Presentation of foreign users | The SwMI should provide sufficient information (i.e. ITSI) for the dispatching or Command & Control system in order to enable accurate presentation of migrated subscriber identity. e.g. In the dispatch system visiting MSs should be presented with an alias revealing the network of origin and the original ISSI of the visiting user (e.g. "B 1234567" as alias on the Dutch network for a Belgian MS with Belgian ISSI 1234567). |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 5.1.6 Migration | This clause describes the requested radio behaviour during migration. The description is based on the behaviour of the radio. The supplier of the network and ISI is asked to supply the underlying mechanisms to support the described behaviour. Two types of migration to another network can be distinguished: • Automatic migration: Migration to the foreign network and back to the home network is done automatic by the radio without any action of the end-user. • Manual migration: Migration to the foreign SwMI and back to the home SwMI is done after manual action of the end-user. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 5.1.6.1 Automatic migration | Advantages: The change from one network to another will be automatic and requires no action from the user. Disadvantages: It is difficult to predict the location where this will happen. (Even possible when the user is in his own country, this due to network coverage of the different networks). ETSI ETSI TR 101 448 V1.1.1 (2005-05) 11 |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 5.1.6.2 Manual migration | Advantages: The change from one network to another network will exactly be determined. (This in either direction). Disadvantages: The change from one network to another network will need an action from the user. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 5.1.6.3 Preferred solution | Operational need: • To be able to use services on the home network as much as possible, the radio should select the home network if available and it should stay on its home-network as long as possible. • The changeover to another network should be automatic. • The radio should clearly show which network is selected. After evaluation of this operational need and the technical possibilities the following implementation was found to be both operationally acceptable and technically feasible. When entering another network and losing coverage from the home network, the radio should automatically select the other network. During the network selection a short period where communications are not available (needed to authenticate the radio on the foreign network) is acceptable. When coming back from the foreign network, the user should be able to switch over to the home network. Also during this switchover a short period where no communications are possible (needed to authenticate the radio on the network) is acceptable. When this manual action is not performed then the radio should automatically search for another network when the signal received from the foreign network is lost, and should select its home network (when available). When switching on a radio, it should select the home network when available. ETSI ETSI TR 101 448 V1.1.1 (2005-05) 12 |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 5.2 Configuration of group ids | Based on the Three-Country Pilot scenarios the following group attachment scenarios have been identified, see figure 1 (examples as seen from the Dutch point of view). Netherlands Belgium Germany E1 E1 E1 1 2 3 4 Figure 1: Group attachment scenarios 1) Attach to home group in foreign SwMI (use of a Dutch group while in Belgium). 2) Attach to a foreign group when registered in the same foreign SwMI (use of a Belgian group while in Belgium). 3) Attach to a foreign group when registered on a different foreign SwMI (use of a Belgian group while in Germany). 4) Attach to a foreign group when registered in home SwMI (use of a Belgian group while in the Netherlands). When attaching to a foreign group, a subscriber could be "generically" permitted to attach to the foreign group, or could be permitted to join a group based on their SwMI of origin. Visitors from other connected SwMIs can attach to groups nominated for visitor attachment, as these will be specifically designated for interoperability. NOTE: Attaching to a foreign group is currently not supported over ISI. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 5.2.1 Pre-provisioning group profiles | As for subscriber migration profiles, local pre-defined migration profiles will be defined in connected SwMIs and migration profile exchange for groups over ISI is not supported. A single pre-defined migration profile is supported in all connected SwMIs. Any migration request using a different pre-defined migration profile number will be rejected. NOTE: Neither group migration profile exchange over ISI or pre-defined group migration profiles are currently supported in the ISI-Mobility Management TIP. The ISI Mobility Management standard does not define the contents of pre-defined migration profiles, therefore as a minimum the pre-defined migration profiles should be based on the mandatory parameters defined in the group migration profile that can be sent over ISI. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 5.2.2 Group attachment approval | When an MS attaches to a group, the home SwMI of the group should be checked to see if group attachment is permitted in the foreign SwMI. There are no required security parameters associated with visiting groups. The group home SwMI should always be checked for authorization of group attachment. The home SwMI should also be required to authorize all subsequent attachments by other MSs. One of the purposes is to allow the Group Home SwMI to maintain an updated list of users attached to the group in all SwMIs. ETSI ETSI TR 101 448 V1.1.1 (2005-05) 13 |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 5.2.3 Group detachment | The home SwMI of the group will be informed when each subscriber detaches from the group. In particular, the last detachment will be specifically notified, as the group will no longer require inter-system services. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6 Services across ISI | The following level of services should be supported for a landmobile and air-mobile user that has migrated to a foreign SwMI. Migration with call restoration is not to be supported. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.1 Possible mobile situations | Figure 2 visualizes the possible situations (positions) of radios involved in ISI communications. NL G B B B NL B B NL NL B B B B G G G Figure 2: Radio positions in an ISI communication ETSI ETSI TR 101 448 V1.1.1 (2005-05) 14 |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.2 Individual call, hook signalling | |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.2.1 Individual call to a subscriber from the home SwMI (while migrated) | 3 3 2 1 NL G B NL B B B B B B B B NL NL G G G SwMI SwMI SwMI Signalling Audio 3 Figure 3: Individual call to a subscriber from the home SwMI • Call Setup (1). • Called party is also in the Visited SwMI. - Local Call (3). • Called party is not in the Visited SwMI. - Visited SwMI will setup the call to the called party's Home SwMI (2). - Home SwMI of the called user reports that the user has migrated, identifying the visited SwMI. - Call will be made to the SwMI where the called party is located (3). ETSI ETSI TR 101 448 V1.1.1 (2005-05) 15 |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.2.2 Individual call to a subscriber from the visited SwMI (while migrated) | 1 3 3 2 NL G B NL B B B B B B B B NL NL G G G SwMI SwMI SwMI Signalling Audio Figure 4: Individual call to a subscriber from the visited SwMI • Call Setup (1). • Called party is also in the Visited SwMI. - Local Call (2). • Called party is not in the Visited SwMI. - The Visited SwMI knows the location of the called party and will transfer the call to the SwMI where the called party is currently located (3). ETSI ETSI TR 101 448 V1.1.1 (2005-05) 16 6.2.3 Individual call to a subscriber from another SwMI (not a subscriber home nor current SwMI) (while migrated) 3 1 3 3 2 NL G B NL B B B B B B B B NL NL G G G SwMI SwMI SwMI Signalling Audio Figure 5: Individual call to a subscriber from another SwMI • Call Setup (1). • Called party is also in the Visited SwMI. - Local Call (3). • Called party is not in the Visited SwMI. - Visited SwMI will setup a call to the Home SwMI of the called user (2). - Home SwMI of the called user reports that the user has migrated, identifying the visited SwMI. - Call will be made to the SwMI where the called party is located (3). ETSI ETSI TR 101 448 V1.1.1 (2005-05) 17 |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.2.4 Individual call to a subscriber (not migrated) | 2 1 NL G B NL B B B B B B B B NL NL G G G SwMI SwMI SwMI Signalling Audio B B 3 3 3 Figure 6: Individual call to a not migrated subscriber • Call Setup (1). • Called party is in the same network. - Local Call (3). • Called party is not in the same network. - Visited SwMI will inquire the called party's location from its Home SwMI (2). - Call will be made to the SwMI where the called party is located (3). ETSI ETSI TR 101 448 V1.1.1 (2005-05) 18 |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.3 Group call | The home SwMI of a group will always be the controlling SwMI for a group call. During group call set-up, the group home SwMI will inform each participating SwMI. It is up to the participating SwMI to connect the call to the attached users in that SwMI. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.3.1 Group call when located in group home SwMI | 1 NL G B Group Home SwMI SwM I SwM I SwM I = Group call setup Figure 7: Group call when located in group home SwMI • Group Call setup to network (1). • The Group Home SwMI checks for attached members. • The Group Home SwMI will connect the call to local attached members and will extend the call to any other SwMI with group members attached. ETSI ETSI TR 101 448 V1.1.1 (2005-05) 19 |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.3.2 Group call when not located in group home SwMI | 1 1 N L G B Group Home SwMI SwMI SwMI SwMI = Group call setup Figure 8: Group call when not located in group home SwMI • Group Call setup to Group Home SwMI (1). • The Group Home SwMI checks the member list for attached members. • The Group Home SwMI will connect the call to local attached members and will transfer the call to any other SwMI with group members attached. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.4 Emergency call | As described in clause 5.2 four different situations can be distinguished: 1) Emergency call to a home group while in a foreign SwMI. 2) Emergency call to a foreign group when registered in the same foreign SwMI. 3) Emergency call to a foreign group when registered on a different foreign SwMI. 4) Emergency call to a foreign group when registered in home SwMI. • Emergency calls should be presented and treated over the ISI maintaining the emergency priority. • In international talkgroups emergency calls should be presented to all involved dispatchers, all dispatchers having equal rights to handle this call. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.5 Telephone call | |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.5.1 Outgoing calls | Outgoing (MS to land) calls should be routed via the local gateway to the public telephone network. ETSI ETSI TR 101 448 V1.1.1 (2005-05) 20 |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.5.2 Incoming calls | Incoming (land to MS) calls will be routed over the ISI to the destination subscriber when the call originates from the gateway in the home SwMI of the called MS. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.6 Status | Group addressed status messages (situation indicators) should be routed to all dispatchers in the group. Emergency status may also be locally interpreted, if meaningful to the SwMI. Status messages addressed to migrated subscribers are not supported. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.7 SDS | Migrated subscribers should be able to send and receive SDS messages. Only SDS type 4 with and without TL should be permitted over ISI. SDS messages can only be sent to or received from the home system. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.8 Packet data | Migrated users should be able to send and receive packet data to their home network. The present view is that packet data service will be implemented via a separate IP gateway. Packet data may form part of an "IPI" rather than the TETRA voice service centric ISI. The only ISI involvement in packet data is the release of the packet data context after migrating away from the visited network. ETSI ETSI TR 101 448 V1.1.1 (2005-05) 21 |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.9 Supplementary Services | Considering that: 1) not all TETRA Supplementary Services are supported in the connected networks; 2) rarely used Supplementary Services may be very complex to implement. A careful evaluation has been done to select Supplementary Services which are essential for operational scenarios. As a result the TETRA supplementary services have been listed below and an indication as to whether or not they should be supported over the ISI has been given. Supported Supplementary Services Calling Line Identification Presentation (CLIP) Talking Party Identification (TPI) Late Entry (LE) Pre-emptive Priority Call (PPC) Barring of Outgoing Calls (BOC) based on locally provisioned profiles Barring of Incoming Calls (BIC) based on locally provisioned profiles Individual Dynamic Group Number Assignment (DGNA) Air-Ground-Air operation (AGA) Not supported Supplementary Services Call Waiting (CW) Call Report (CR) Call Forwarding (CF) List Search Call (LSC) Call Authorized by Dispatcher (CAD) Short Number Addressing (SNA) Area Selection (AS) Access Priority (AP) Priority Call (PC) Call Hold (HOLD) Call Completion to Busy Subscriber (CCBS) Include Call (IC) Discreet Listening (DL) Ambience Listening (AL) Call Completion on No Reply (CCNR) Call Retention (CRT) Calling Line Identification Restriction (CLIR) COnnected Line identification Presentation (COLP) COnnected Line identification Restriction (COLR) ETSI ETSI TR 101 448 V1.1.1 (2005-05) 22 Group addressed Dynamic Group Number Assignment (DGNA) |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.9.1 Calling line identification presentation | Calling Line Identification Presentation for telephone calls should be available for intersystem calls, depending on the capabilities of the connected SwMI. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.9.2 Talking party identification | TPI should be available to intersystem calls with no change of characteristics. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.9.3 Late entry | LE should be available to intersystem calls with no change of characteristics. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.9.4 Pre-emptive priority call | The ISI should be considered a pre-emptable resource, and calls in progress will be dropped if necessary to set-up higher priority calls. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.9.5 Barring of outgoing calls | Each SwMI can bar calls based on locally provisioned profiles. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.9.6 Barring of incoming calls | Each SwMI can bar calls based on locally provisioned profiles. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.9.7 Individual DGNA | Individual DGNA modifies the talkgroup list inside a radio by adding or removing groups. To allow flexibility in cross system operations, it is highly desirable to be able to use DGNA in cross border operations. Therefore the manufacturer is asked to make an optional offer for the following functionality: An authorized dispatcher should be able to send talkgroups to both foreign and home MSs. Using DGNA over the ISI the dispatcher should be able to send groups to foreign MSs and migrated MSs of the own network. To maintain a clear responsibility for the talkgroups only the Group home SwMI should be able to DGNA a talkgroup to a radio. Group addressed DGNA will not be supported for migrating MSs over the ISI. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.9.8 Enable/disable | Enable and disable commands should be supported from the home system to its migrated MSs. Enable and disable should not be initiated by a user of the visited SwMI. NOTE: Enable/disable is currently not supported over ISI. |
5dd15760ca0122e1bdf353e6aec7f413 | 101 448 | 6.9.9 Air-ground-air operation | Air-mobile users should have the same possibilities to migrate and communicate as landmobile users. |
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