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8.3.3.3 Information flows
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8.3.3.3.1 Root application and profile update notification
If the MMTel Enabler Server interacts with the SEAL notification server to use the notification service, the Notification message specified in clause 17.3.2.4 applies to the Root application and profile update notification. The usage of the information elements in MMTel service is clarified as below: - The identifier ...
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8.3.3.3.2 Root application notification
Table 8.3.3.3.2-1 describes information elements for the Root application notification from the MMTel Enabler Server to the MMTel Enabler Client. Table 8.3.3.3.2-1: Information elements for Root application notification Information element Status Description Update Indication M Indicates whether the Root applica...
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8.3.3.3.3 MMTel Enabler Client subscribes to the MMTel Enabler Server request
Table 8.3.3.3.3-1 describes information elements for the MMTel Enabler Client subscribes to the MMTel Enabler Server request. Table 8.3.3.3.3-1: Information elements for MMTel Enabler Client subscribes to the MMTel Enabler Server request Information element Status Description MMTel Enabler Client ID M Identity...
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8.4 Application calling enablement
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8.4.1 General
The following clauses specify procedures and information flows for Application calling enablement.
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8.4.2 Application calling service API with Data Channel capability
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8.4.2.1 General
The MMTel Enabler Server exposes the Application calling service API with Data Channel capability to the Applications in order to support establishing a call between Application and DCMTSI client.
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8.4.2.2 Procedure
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8.4.2.2.1 Establishing an Application Call with Data Channel capability between non-IMS application and DCMTSI client
Figure 8.4.2.2.1-1 illustrates the operation to establish an Application Call with Data Channel capability between non-IMS application and DCMTSI client. Pre-conditions: 1. The Application is authorized to use Application calling service API provided by the MMTel Enabler Server. 2. The MMTel Enabler Server is author...
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8.4.2.3 Information flows
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8.4.2.3.1 Application Call establishment request
The information elements of Application Call establishment request are as same as the elements in Table 8.4.3.3.1-1.
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8.4.2.3.2 Application Call establishment response
The information elements of Application Call establishment response are as same as the elements in Table 8.4.3.3.2-1.
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8.4.3 Third-Party Call service API with Data Channel capability
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8.4.3.1 General
The MMTel Enabler Server exposes the Third-Party Call service API with Data Channel capability to the Vertical service provider in order to support establishing a call between two UEs.
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8.4.3.2 Procedure
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8.4.3.2.1 Establishing a Third-Party Call with Data Channel capability
Figure 8.4.3.2.1-1 illustrates the operation to establish a Third-Party Call with Data Channel capability. Pre-conditions: 1. The Vertical service provider is authorized to use Third-Party Call service API provided by the MMTel Enabler Server. 2. The MMTel Enabler Server is authorized to use the IMS DC capability A...
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8.4.3.3 Information flows
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8.4.3.3.1 Third-Party Call with DC capability establishment request
Table 8.4.3.3.1-1 describes information elements for the Third-Party Call with DC capability establishment request from the Application Server to the MMTel Enabler Server. Table 8.4.3.3.1-1: Third-Party Call with DC capability establishment request Information element Status Description Related OMA API Element Or...
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8.4.3.3.2 Third-Party Call with DC capability establishment response
Table 8.4.3.3.2-1 describes information elements for the Third-Party Call with DC capability establishment response from the Application Server to the MMTel Enabler Server. Table 8.4.3.3.2-1: Third-Party Call with DC capability establishment response Information element Status Description Related OMA API Element ...
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8.4.4 Establishing an Application Call with Data Channel capability (A2P)
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8.4.4.1 Procedure
Figure 8.4.4-1 illustrates the operation to establish an Application Call with Data Channel capability between the Application and the MMTel Enabler Server in order to add an A2P Data Channel to an existing IMS session of the user on UE1 in alignment with the A2P flow specified in 3GPP TS 23.228 [3]. Pre-conditions: ...
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8.4.4.2 Information flows
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8.4.4.2.1 Application Add Data Channel media to UE1 session (A2P) request
Table 8.4.4.2.1-1: Application Add Data Channel media to UE1 session (A2P) request Information element Status Description Data Channel APPID M The identifier of the DC application. Session ID M The session identifier of the session on which MMTel Enabler Server must add the new media. Media resource informati...
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8.4.4.2.2 Application Add Data Channel media to UE1 session (A2P) response
Table 8.4.4.2.2-1: Application Add Data Channel media (A2P) response Information element Status Description Session ID M The session identifier of the session on which MMTel Enabler Server must add the new media. Result M Indicates the Notification of Application of DC media info (A2P) request was successful...
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8.4.4.2.3 Notify Application of DC media info (A2P) request
Table 8.4.4.2.3-1: Notify Application of DCH media info (A2P) request Information element Status Description Session ID M The session identifier of the session on which MMTel Enabler Server must add the new media. Notification address M The address where the call related notification, e.g. whether the call bet...
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8.4.4.2.4 Notify Application of DC media info (A2P) response
Table 8.4.4.2.4-1: Notify Application of DC media info (A2P) response Information element Status Description Session ID M The session identifier of the session on which MMTel Enabler Server must add the new media. Result M Indicates the Notification of Application of DC media info (A2P) request was successfu...
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8.4.5 Application calling service API with Data Channel capability
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8.4.5.1 Procedure
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8.4.5.1.1 Establishing an Application Call with Data Channel capability (P2A)
Figure 8.4.5.1.1-1 illustrates the operation to establish an Application Call with Data Channel capability between a user (on UE1) and a Data Chanel (DC) Application via the MMTel Enabler Server. Pre-conditions: 1. The Application can use DC (supports the media set information for DC) and is authorized to use the ser...
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8.4.5.2 Information flows
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8.4.5.2.1 Notify DC Application of MDC2 media (P2A) request
Table 8.4.5.2.1-1: Notify DC Application of MDC2 media (P2A) request Information element Status Description Session ID M The session identifier of the session on which MMTel Enabler Server must add the new media. Media resource information O The MDC2 media information requested by the UE1 to be sent over the D...
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8.4.5.2.2 Notify DC Application of MDC2 media (P2A) response
Table 8.4.5.2.2-1: Notify DC Application of MDC2 media (P2A) response Information element Status Description Session ID M The session identifier of the session on which MMTel Enabler Server must add the new media. Result M Indicates the Notification of Application of DC media info (A2P) request was successfu...
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8.5 Multiple call control handling coordination among different Application Servers
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8.5.1 General
When receiving call control requests from multiple Application Servers, the MMTel Enabler Server provides call control handling consolidation and coordination.
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8.5.2 Procedure
Figure 8.5.2-1 illustrates the procedure of multiple call control handling coordination among different Application Servers. Pre-conditions: 1. The Application Servers and MMTel Enabler Server have mutually authenticated each other. 2. The call control handling policy (e.g. the priority of each Application Server) i...
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8.5.3 Information flows
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8.5.3.1 Call control result notification
Table 8.5.3.1-1 describes information elements for call control result notification request from the MMTel Enabler Server to the Application server. Table 8.5.3.1-1: Call control result notification request Information element Status Description Final result of the call control request M Indicates the final resu...
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9 Deployment Guideline
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9.1 General
This clause describes deployments of the functional model specified in clause 6.
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9.2 MMTel Enabler server deployed in PLMN operator domain
The MMTel Enabler server is recommended to be deployed in the PLMN operator domain. Figure 9.2-1 illustrates the MMTel Enabler server deployed in PLMN operator domain. Figure 9.2-1: MMTel Enabler server deployed in PLMN operator domain The Application server can be deployed in PLMN operator domain or Application s...
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1 Scope
The present document defines the Stage 2 service description for the Evolved 3GPP Packet Switched Domain - also known as the Evolved Packet System (EPS) in this document. The Evolved 3GPP Packet Switched Domain provides IP connectivity using the Evolved Universal Terrestrial Radio Access Network (E-UTRAN). The specifi...
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2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present document. - References are either specific (identified by date of publication, edition number, version number, etc.) or non‑specific. - For a specific reference, subsequent revisions do not apply. -...
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3 Definitions and abbreviations
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3.1 Definitions
For the purposes of the present document, the terms and definitions given in TR 21.905 [1] and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905 [1]. Disaster Condition: As defined in TS 22.261 [97]. Disaster Inbound Roamer: As defi...
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3.2 Abbreviations
For the purposes of the present document, the abbreviations given in TR 21.905 [1] and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905 [1]. 5GS 5G System AF Application Function ARP Allocation and Retention Prior...
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4 Architecture model and concepts
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4.1 General concepts
Local breakout of traffic via the visited PLMN is supported, when network policies and user subscription allow it. Local breakout may be combined with support for multiple simultaneous PDN connections, described in clause 5.10. CIoT EPS Optimisations provide improved support of small data transfer, described in clause...
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4.2 Architecture reference model
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4.2.1 Non-roaming architecture
Figure 4.2.1-1: Non-roaming architecture for 3GPP accesses Figure 4.2.1-2: Non-roaming architecture for 3GPP accesses. Single gateway configuration option NOTE 1: Also in this configuration option, S5 can be used between non collocated Serving Gateway and PDN Gateway. NOTE 2: Additional interfaces for 2G/3G acce...
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4.2.2 Roaming architecture
Figure 4.2.2-1: Roaming architecture for 3GPP accesses. Home routed traffic NOTE 1: Additional interfaces/reference points for 2G/3G accesses are documented in TS 23.060 [7]. The figures 4.2.2-2 and 4.2.2-3 represent the Roaming with local breakout case with Application Function (AF) in the Home Network and in the ...
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4.2.3 Reference points
S1-MME: Reference point for the control plane protocol between E-UTRAN and MME. S1-U: Reference point between E-UTRAN and Serving GW for the per bearer user plane tunnelling and inter eNodeB path switching during handover. S1-U does not apply to the Control Plane CIoT EPS Optimisation. S3: It enables user and bearer ...
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4.2.4 Warning System architecture
Refer to TS 23.041 [48] and TS 23.002 [71] for the Warning System architecture.
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4.2.5 Radio Capability signalling optimization architecture
Figure 4.2.5-1: RACS architecture Figure 4.2.5-1 depicts the EPS architecture supporting RACS. RACS is further described in clause 5.11.3a. EPS architecture supporting provisioning of UCMF is described in TS 23.682 [74].
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4.3 High level functions
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4.3.1 General
The following list gives the logical functions performed within this system. Several functional groupings (meta functions) are defined and each encompasses a number of individual functions: - Network Access Control Functions. - Packet Routing and Transfer Functions. - Mobility Management Functions. - Security Funct...
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4.3.2 Network access control functions
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4.3.2.1 General
Network access is the means by which a user is connected to the evolved packet core system.
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4.3.2.2 Network/Access network selection
It is the means by which a UE selects a PLMN/Access network from which to gain connectivity. The network/access network selection procedure varies for different access technologies. For 3GPP access networks, the network selection principles are described in TS 23.122 [10]. For 3GPP access networks, the access network s...
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4.3.2.3 Authentication and authorisation function
This function performs the identification and authentication of the service requester, and the validation of the service request type to ensure that the user is authorised to use the particular network services. The authentication function is performed in association with the Mobility Management functions.
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4.3.2.4 Admission control function
The purpose of admission control is to determine if the requested resources are available, and then reserve those resources.
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4.3.2.5 Policy and Charging Enforcement Function
This includes all the functionality of PCEF as defined by TS 23.203 [6]. The PCEF encompasses service data flow detection, policy enforcement and flow based charging functionalities as defined in TS 23.203 [6].
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4.3.2.6 Lawful Interception
Lawful interception is the action, performed by a network operator / access provider / service provider, of making available certain information and providing that information to a law enforcement monitoring facility. 4.3.2a Support for Dual Connectivity Dual Connectivity involves two RAN nodes, i.e. Master and Secon...
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4.3.3 Packet routing and transfer functions
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4.3.3.1 General
A route is an ordered list of nodes used for the transfer of packets within and between the PLMN(s). Each route consists of the originating node, zero or more relay nodes and the destination node. Routing is the process of determining and using, in accordance with a set of rules, the route for transmission of a message...
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4.3.3.2 IP header compression function
The IP header compression function optimises use of radio capacity by IP header compression mechanisms. When Control Plane CIoT EPS Optimisation is supported for PDN connections of IP PDN Type, if the IP header compression based on ROHC framework IETF RFC 5795 [77] is implemented in the MME and the UE, the ROHC profil...
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4.3.3.3 Packet screening function
The packet screening function provides the network with the capability to check that the UE is using the exact IPv4-Address and/or IPv6-Prefix that was assigned to the UE.
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4.3.3.4 IP Multicast Forwarding between a network accessed by LIPA and a UE
The Home eNodeB L-GW should support IP forwarding of packets to multicast groups between the UE and the network accessed by LIPA.
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4.3.4 Security functions
The security functions are described in clause 5.3.10.
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4.3.5 Mobility management functions
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4.3.5.1 General
The mobility management functions are used to keep track of the current location of a UE. Intra-RAT mobility for NB-IoT UEs is supported. Inter-RAT idle mode mobility between NB-IoT and WB-EUTRAN/UTRAN/GERAN is supported. Tracking area list management as defined in clause 4.3.5.3 is required to ensure that at inter-R...
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4.3.5.2 Reachability Management for UE in ECM-IDLE state
The location of a UE in ECM-IDLE state is known by the network on a Tracking Area List granularity. All cells of the Tracking Areas in which a UE in ECM-IDLE is currently registered needs to be taken into account for paging. The UE may be registered in multiple Tracking Areas. All the tracking areas in a Tracking Area ...
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4.3.5.3 Tracking Area list management
Tracking Area list management comprises the functions to allocate and reallocate a Tracking Area Identity list to the UE. All the tracking areas in a Tracking Area List to which a UE is registered are served by the same serving MME. The "tracking area list concept" is used with E-UTRAN. With this concept, when the UE ...
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4.3.5.4 Inter-eNodeB mobility anchor function
The Inter-eNodeB Mobility Anchor is the functional entity that anchors the user plane for E-UTRAN mobility.
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4.3.5.5 Inter-3GPP mobility anchor function
The Inter-3GPP Mobility Anchor is the functional entity that anchors the user plane for mobility between 3GPP 2G/3G access systems and the E-UTRA access system.
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4.3.5.6 Idle mode signalling reduction function
The Idle mode Signalling Reduction (ISR) function provides a mechanism to limit signalling during inter-RAT cell-reselection in idle mode (ECM-IDLE, PMM-IDLE, GPRS STANDBY states). NOTE 1: The Idle mode Signalling Reduction function is mandatory for E-UTRAN UEs that support GERAN and/or UTRAN and optional for core net...
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4.3.5.7 Mobility Restrictions
Mobility Restrictions comprises the functions for restrictions to mobility handling of a UE in E-UTRAN access. The Mobility Restriction functionality is provided by the UE, the radio access network and the core network. Mobility Restriction functionality in state ECM-IDLE is executed in UE based on information receive...
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4.3.5.8 IMS voice over PS Session Supported Indication
The serving PLMN shall send an indication toward the UE during the Attach procedure and Tracking Area Update procedures if an IMS voice over PS session is supported. The serving PLMN uses this indicator to indicate to the UE whether it can expect a successful IMS voice over PS session according to TS 22.173 [73] with a...
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4.3.5.9 Voice domain preference and UE's usage setting
If the UE supports CS fallback, or the UE is configured to support IMS voice, or both, the UE shall include the information element "Voice domain preference and UE's usage setting" in Attach Request, Tracking Area Update Request and Routing Area Update Request messages. The purpose of this information element is to sig...
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4.3.5.10 Preferred and Supported Network Behaviour
A UE includes in a Preferred Network Behaviour indication the Network Behaviour the UE can support and what it would prefer to use. The Preferred Network Behaviour includes this information: - Whether Control Plane CIoT EPS Optimisation is supported. - Whether User Plane CIoT EPS Optimisation is supported. - Whethe...
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4.3.6 Radio Resource Management functions
Radio resource management functions are concerned with the allocation and maintenance of radio communication paths, and are performed by the radio access network. RRM includes both idle mode and connected mode. The RRM strategy in E-UTRAN may be based on user specific information. To support radio resource management ...
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4.3.7 Network management functions
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4.3.7.1 General
Network management functions provide mechanisms to support O&M functions related to the Evolved Packet System. 4.3.7.1a GTP-C signalling based Load and Overload Control 4.3.7.1a.1 GTP-C Load Control GTP-C Load Control feature is an optional feature which allows a GTP control plane node to send its Load Control Infor...
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4.3.7.2 Load balancing between MMEs
The MME Load Balancing functionality permits UEs that are entering into an MME Pool Area to be directed to an appropriate MME in a manner that achieves load balancing between MMEs. This is achieved by setting a Weight Factor for each MME, such that the probability of the eNodeB selecting an MME is proportional to its W...
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4.3.7.3 Load re-balancing between MMEs
The MME Load Re-balancing functionality permits UEs that are registered on an MME (within an MME Pool Area) to be moved to another MME. NOTE 1: An example use for the MME Load Re-balancing function is for the O+M related removal of one MME from an MME Pool Area. NOTE 2: Typically, this procedure should not be used wh...
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4.3.7.4 MME control of overload
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4.3.7.4.1 General
The MME shall contain mechanisms for avoiding and handling overload situations. These can include the use of NAS signalling to reject NAS requests from UEs. In addition, under unusual circumstances, the MME shall restrict the load that its eNodeBs are generating on it if it is configured to enable the overload restric...
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4.3.7.4.2 NAS level congestion control
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4.3.7.4.2.1 General
NAS level congestion control contains the functions: "APN based congestion control" and "General NAS level Mobility Management control". The use of the APN based congestion control is for avoiding and handling of EMM and ESM signalling congestion associated with UEs with a particular APN. Both UEs and network shall su...
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4.3.7.4.2.2 APN based Session Management congestion control
The APN based Session Management congestion control may be activated by MME due to e.g. congestion situation at MME, or by OAM at MME, or by a restart or recovery condition of a PDN GW, or by a partial failure or recovery of a PDN GW for a particular APN(s). The MME may reject the EPS Session Management (ESM) requests...
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4.3.7.4.2.3 APN based Mobility Management congestion control
The MME may perform the APN based congestion control for UEs with a particular subscribed APN by rejecting Attach procedures with a Mobility Management back-off timer. When congestion control is active for UEs with a particular subscribed APN, a Mobility Management back-off timer may be sent by the MME to UE. If MME ...
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4.3.7.4.2.4 General NAS level Mobility Management congestion control
Under general overload conditions the MME may reject Mobility Management signalling requests from UEs. When a NAS request is rejected, a Mobility Management back-off timer may be sent by the MME and MME may store the back-off time per UE if a request without the low access priority indicator is rejected by the MME and ...
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4.3.7.4.2.5 Group specific NAS level congestion control
The group specific NAS level congestion control applies to a specific group of UEs. Each group has a group identifier assigned. A UE belongs to a group, if the corresponding group identifier is stored in the UE's subscription data in the HSS. A UE may belong to multiple groups and the MME may perform the Group specifi...
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4.3.7.4.2.6 APN and group specific NAS level congestion control
The APN and group specific NAS level congestion control is the intersection of APN specific NAS level congestion control and Group specific NAS level congestion control, i.e. it applies to a specific group of UEs with a particular subscribed APN. Each group of UEs has a group identifier assigned and stored in the HSS. ...
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4.3.7.4.2.7 Control Plane data specific NAS level congestion control
Under overload conditions the MME may restrict requests from UEs for data transmission via Control Plane CIoT EPS Optimisation. A Control Plane data back-off timer may be returned by the MME (e.g.in Attach/TAU/RAU Accept messages, Service Reject message or Service Accept message). While the Control Plane data back-off ...
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4.3.7.5 PDN GW control of overload
The PDN GW may provide mechanisms for avoiding and handling overload situations. These include the rejection of PDN connection requests from UEs. The PDN GW may detect APN congestion and start and stop performing overload control based on criteria such as: - Maximum number of active bearers per APN; and/or - Maximum...
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4.3.8 Selection functions
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4.3.8.1 PDN GW selection function (3GPP accesses)
The PDN GW selection function allocates a PDN GW that shall provide the PDN connectivity for the 3GPP access. The function uses subscriber information provided by the HSS and possibly additional criteria such as SIPTO/LIPA support per APN configured in the SGSN/MME, UE support for dual connectivity with NR, 15 EPS bear...
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4.3.8.2 Serving GW selection function
The Serving GW selection function selects an available Serving GW to serve a UE. The selection bases on network topology, i.e. the selected Serving GW serves the UE's location and for overlapping Serving GW service areas, the selection may prefer Serving GWs with service areas that reduce the probability of changing th...
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4.3.8.3 MME selection function
The MME selection function selects an available MME for serving a UE. The selection is based on network topology, i.e. the selected MME serves the UE's location and for overlapping MME service areas, the selection may prefer MMEs with service areas that reduce the probability of changing the MME. When a MME/SGSN select...