6 PLMN basic interfaces and reference points

23.0023GPPNetwork architectureRelease 17TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

The implementation of the mobile service with international roaming implies the exchange of data between the equipment involved in the service. The same No.7 signalling network should be used to transfer these data and the call-related signalling information.

Editor’s note: Either the difference between interface and reference point should be clearly provided, or only one of the terms should be used.

6.1 Interfaces between Mobile Station and the Fixed Infrastructure

6.1.1 Interface between Mobile Station and Base Station System (Um-interface)

The interface between the MS and the BSS is specified in the 44- and 45-series of Technical Specifications.

6.1.2 Interface between User Equipment and Radio Network System (Uu-interface)

The interface between the UE and the RNS is specified in the 24- and 25-series of Technical Specifications.

6.1.3 Interface between User Equipment and Evolved UTRAN (E-UTRAN Uu-interface)

The interface between the UE and the E-UTRAN is specified in the 36-series of Technical Specifications.

6.2 Interface between the Core Network and the Access Network

6.2.1 Interfaces between the CS domain and the Access Network

6.2.1.1 Interface between the MSC and Base Station System (A-interface)

The interface between the MSC and its BSS is specified in the 48-series of Technical Specifications.

The BSS-MSC interface is used to carry information concerning:

– BSS management;

– call handling;

– mobility management.

6.2.1.2 Interface between the MSC and Base Station System (Iu_CS interface)

The interface between the MSC and its BSS is specified in the 25.41x-series of Technical Specifications.

The BSS-MSC interface is used to carry information concerning:

– BSS management;

– call handling;

– mobility management;

6.2.1.3 Interface between the MSC and RNS (Iu_CS interface)

The interface between the MSC and its RNS is specified in the 25.41x-series of Technical Specifications.

The RNS-MSC interface is used to carry information concerning:

– RNS management;

– call handling;

– mobility management.

6.2.2 Interfaces between the PS domain and the Access Network

6.2.2.1 Interface between SGSN and BSS (Gb-interface)

The BSS-SGSN interface is used to carry information concerning:

– packet data transmission;

– mobility management.

The Gb interface is defined in TS 48.014 [44], TS 48.016 [45] and TS 48.018 [46].

6.2.2.2 Interface between SGSN and BSS (Iu_PS-interface)

The BSS-SGSN interface is used to carry information concerning:

– packet data transmission;

– mobility management.

The Iu_PS interface is defined in the 25.41x-series of 3GPP Technical Specifications.

6.2.2.3 Interface between SGSN and RNS (Iu_PS-interface)

The RNS-SGSN interface is used to carry information concerning:

– packet data transmission;

– mobility management.

The Iu_PS interface is defined in the 25.41x-series of Technical Specifications.

6.2.3 Interfaces between the Evolved Packet Core and the Access Network

6.2.3.1 Interface between MME and E-UTRAN (S1-MME-interface)

Reference point for the control plane protocol between E-UTRAN and MME. This interface is defined in the TS 36.41x-series of Technical Specifications and in TS 24.301 [89].

6.2.3.2 Interface between S-GW and E-UTRAN (S1-U-interface)

Reference point between E-UTRAN and S GW for the per bearer user plane tunnelling. This interface is defined in TS 29.281 [126].

6.3 Interfaces internal to the Access Network

6.3.1 Interface between BSC and BTS (Abis-interface)

When the BSS consists of a Base Station Controller (BSC) and one or more Base Transceiver Stations (BTS), this interface is used between the BSC and BTS to support the services offered to the GSM users and subscribers.

The interface also allows control of the radio equipment and radio frequency allocation in the BTS.

The interface is specified in the 48.5x-series of Technical Specifications.

6.3.2 Interface between RNC and Node B (Iub-interface)

When the RNS consists of a Radio Network Controller (RNC) and one or more Node B, this interface is used between the RNC and Node B to support the services offered to the UMTS users and subscribers.

The interface also allows control of the radio equipment and radio frequency allocation in the Node B.

The interface is specified in the 25.43x series of Technical Specifications.

6.3.3 Interface between two RNCs (Iur-interface)

This interface is defined in the 25.42x series of Technical Specifications.

6.3.4 Interface between two eNBs (X2-interface)

This is a logical interface between two eNBs. Whilst logically representing a point to point link between eNBs, the physical realization need not be a point to point link. This interface is defined in the TS 36.42x-series of Technical Specifications.

6.3.5 Interface between HNB and HNB-GW(Iuh-interface)

This interface is specified in the TS 25.467 [114], TS 25.468 [115] and TS 25.469 [116].

6.4 Interfaces internal to the Core Network

6.4.1 Interfaces internal to the CS domain

6.4.1.1 Interface between the MSC server and its associated VLR (B-interface)

The VLR is the location and management database for the mobile subscribers roaming in the area controlled by the associated MSC server(s). Whenever the MSC server needs data related to a given mobile station currently located in its area, it interrogates the VLR. When a mobile station initiates a location updating procedure with an MSC server, the MSC server informs its VLR which stores the relevant information. This procedure occurs whenever an MS roams to another location area. Also, when a subscriber activates a specific supplementary service or modifies some data attached to a service, the MSC server informs (via the VLR) the HLR which stores these modifications and updates the VLR if required.

This interface is internal to the MSC server /VLR; signalling on it is not standardised.

6.4.1.2 Interface between the HLR and the MSC server (C-interface)

The Gateway MSC server must interrogate the HLR of the required subscriber to obtain routing information for a call or a short message directed to that subscriber.

Signalling on this interface uses the Mobile Application Part (MAP), which in turn uses the services of Transaction Capabilities (see TS 29.002 [26]).

For CAMEL purposes, this interface is used as described in TS 23.078 [10c]. It is used e.g. at terminating calls to exchange routeing information, subscriber status, location information, subscription information, etc.

6.4.1.3 Interface between the HLR and the VLR (D-interface)

This interface is used to exchange the data related to the location of the mobile station and to the management of the subscriber. The main service provided to the mobile subscriber is the capability to set up or to receive calls within the whole service area. To support this, the location registers have to exchange data. The VLR informs the HLR of the location of a mobile station managed by the latter and provides it (either at location updating or at call set-up) with the roaming number of that station. The HLR sends to the VLR all the data needed to support the service to the mobile subscriber. The HLR then instructs the previous VLR to cancel the location registration of this subscriber. Exchanges of data may occur when the mobile subscriber requires a particular service, when he wants to change some data attached to his subscription or when some parameters of the subscription are modified by administrative means.

Signalling on this interface uses the Mobile Application Part (MAP), which in turn uses the services of Transaction Capabilities (see TS 29.002 [26]).

For CAMEL purposes, this interface is used to send the CAMEL related subscriber data to the visited PLMN and for provision of MSRN. The interface is also used for the other purposes described in TS 23.078 [10c], e.g. to retrieve subscriber status and location information of the mobile subscriber or to indicate suppression of announcement for a CAMEL service.

6.4.1.4 Interface between MSC servers or MSC server and IP-SM-GW (E-interface)

When a mobile station moves from one MSC area to another during a call, a handover procedure has to be performed in order to continue the communication. For that purpose the MSC servers have to exchange data to initiate and then to realise the operation.

After the handover operation has been completed, the MSC servers will exchange information to transfer A‑ or Iu‑ interface signalling as defined in TS 23.009 [6].

When a short message is to be transferred between a Mobile Station and Short Message Service Centre (SC), in either direction, this interface is used to transfer the message between the MSC server serving the Mobile Station and the MSC server which acts as the interface to the SC. or between the IP-SM-GW serving the Mobile Station and the MSC server which acts as the interface to the SC.

Signalling on this interface uses the Mobile Application Part (MAP), which in turn uses the services of Transaction Capabilities (see TS 29.002 [26]).

6.4.1.5 Interface between MSC server and EIR (F-interface)

This interface is used between MSC server and EIR to exchange data, in order that the EIR can verify the status of the IMEI retrieved from the Mobile Station.

Signalling on this interface uses the Mobile Application Part (MAP), which in turn uses the services of Transaction Capabilities (see TS 29.002 [26]).

6.4.1.6 Interface between VLRs (G-interface)

When a mobile subscriber moves from a VLR area to another Location Registration procedure will happen. This procedure may include the retrieval of the IMSI and authentication parameters from the old VLR.

Signalling on this interface uses the Mobile Application Part (MAP), which in turn uses the services of Transaction Capabilities (see TS 29.002 [26]).

6.4.1.7 Reference point (G)MSC server – CS-MGW (Mc Reference Point)

The Mc reference point describes the interfaces between the MSC Server and CS-MGW, and between the GMSC Server and CS-MGW. It has the following properties:

– full compliance with the H.248 [52] standard, baseline work of which is currently carried out in ITU-T Study Group 16, in conjunction with IETF MEGACO WG.

– flexible connection handling which allows support of different call models and different media processing purposes not restricted to H.323 [54] usage.

– open architecture where extensions/Packages definition work on the interface may be carried out.

– dynamic sharing of MGW physical node resources. A physical MGW can be partitioned into logically separate virtual MGWs/domains consisting of a set of statically allocated Terminations.

– dynamic sharing of transmission resources between the domains as the MGW controls bearers and manage resources according to the H.248 [52] protocols.

The functionality across the Mc reference point will need to support mobile specific functions such as SRNS relocation/handover and anchoring. It is expected that current H.248/IETF Megaco [52] standard mechanisms can be applied to enable this.

6.4.1.8 Reference Point MSC Server – GMSC Server (Nc Reference Point)

Over the Nc reference point, the Network-Network based call control is performed. Examples of this are ISUP or an evolvement of ISUP for bearer independent call control (BICC). Different options for signalling transport on Nc shall be possible including IP.

6.4.1.9 Reference Point CS-MGW – CS-MGW (Nb Reference Point)

Over the Nb reference point the bearer control and transport are performed. The transport may be RTP/UDP/IP [59], [60] or AAL2 (I.363-2) [57] for transport of user data. Different options for user data transport and bearer control shall be possible on Nb, for example: AAL2/Q.AAL2, STM/none, RTP/H.245 [58], IPBC.

6.4.1.10 Reference Point between the CSS and the VLR (Hv Reference Point)

This reference point is used to transfer to the VLR the CSG subscription information stored in the VPLMN for roaming UEs.

Signalling on this interface uses the Mobile Application Part (MAP), which in turn uses the services of Transaction Capabilities (TCAP) (see TS 29.002 [26]).

6.4.2 Interfaces internal to the PS domain (GPRS)

6.4.2.1 Interface between SGSN and HLR (Gr-interface)

This interface is used to exchange the data related to the location of the mobile station and to the management of the subscriber. The main service provided to the mobile subscriber is the capability to transfer packet data within the whole service area. The SGSN informs the HLR of the location of a mobile station managed by the latter. The HLR sends to the SGSN all the data needed to support the service to the mobile subscriber. Exchanges of data may occur when the mobile subscriber requires a particular service, when he wants to change some data attached to his subscription or when some parameters of the subscription are modified by administrative means.

Signalling on this interface uses the Mobile Application Part (MAP), which in turn uses the services of Transaction Capabilities (TCAP) (see TS 29.002 [26]).

6.4.2.2 Interface between SGSN and GGSN (Gn- and Gp-interface)

These interfaces are used to support mobility between the SGSN and GGSN. The Gn interface is used when GGSN and SGSN are located inside one PLMN. The Gp-interface is used if GGSN and SGSN are located in different PLMNs. The Gn/Gp interface also includes a part which allows SGSNs to communicate subscriber and user data, when changing SGSN.

Signalling on this interface uses the User Datagram Protocol, UDP/IP [59]. The Gn/Gp interface is defined in TS 29.060 [51].

6.4.2.3 Signalling Path between GGSN and HLR (Gc-interface)

This optional signalling path may be used by the GGSN to retrieve information about the location and supported services for the mobile subscriber, to be able to activate a packet data network address.

There are two alternative ways to implement this signalling path:

– if an SS7 interface is implemented in the GGSN, signalling between the GGSN and the HLR uses the Mobile Application Part (MAP), which in turn uses the services of Transaction Capabilities (TCAP) (see TS 29.002 [26]);

– if there is no SS7 interface in the GGSN, any GSN in the same PLMN and which has an SS7 interface installed can be used as a GTP to MAP protocol converter, thus forming a signalling path between the GGSN and the HLR.

6.4.2.4 Interface between SGSN and EIR (Gf-interface)

This interface is used between SGSN and EIR to exchange data, in order that the EIR can verify the status of the IMEI retrieved from the Mobile Station.

Signalling on this interface uses the Mobile Application Part (MAP), which in turn uses the services of Transaction Capabilities (TCAP) (see TS 29.002 [26]).

6.4.2.5 Reference Point between the CSS and the Gn/Gp SGSN (Ghv Reference Point)

This reference point is used to transfer to the Gn/Gp SGSN the CSG subscription information stored in the VPLMN for roaming UEs.

Signalling on this interface uses the Mobile Application Part (MAP), which in turn uses the services of Transaction Capabilities (TCAP) (see TS 29.002 [26]).

6.4.3 Interfaces used by CS and PS domains

6.4.3.1 Interface between MSC/VLR and SGSN (Gs-interface) for GPRS

The SGSN may send location information to the MSC/VLR via the optional Gs interface. The SGSN may receive paging requests from the MSC/VLR via the Gs interface. The MSC/VLR may indicate to an SGSN, via the Gs interface, that an MS is engaged in a service handled by the MSC.

Signalling on this interface uses connectionless SCCP (without TCAP). SCCP Global Title (GT) is used for addressing. The Gs-interface is defined in TS 29.016 [48] and TS 29.018 [49].

6.4.3.2 Interface between HLR/HSS and AuC (H-Interface)

When an HLR/HSS receives a request for authentication and ciphering data for a Mobile Subscriber and it does not hold the requested data, the HLR/HSS requests the data from the AuC. The protocol used to transfer the data over this interface is not standardised.

6.4.3.3 Interface between SGSN/IP-SM-GW and SMS-GMSC/SMS-IWMSC (Gd/Gdd-Interface) for GPRS

The Gd interface may be used to transfer short messages between SGSN. IP-SM-GW and SMS-GMSC/SMS-IWMSC over GPRS.

Signalling on the Gd interface uses the Mobile Application Part (MAP) (see TS 29.002 [26]).

The Gdd interface may be used to to transfer short messages between SGSN supporting EPS interfaces, IP-SM-GW and SMS GMSC/SMS IWMSC.

Signalling on the Gdd interface uses the Diameter SGd application (see TS 29.338 [135]).

6.4.3.4 Interface between MSC/VLR and MME (SGs-interface) for EPC

The SGs interface is the reference point between the MME and MSC/VLR which is used for the mobility management and paging procedures between EPS and CS domain, and it is based on the Gs interface procedures.

The SGs interface is used to provide Fallback for Location Services (LCS) and Call Independent Supplementary Services (SS).

The SGs interface is also used for the delivery of both mobile originating and mobile terminating SMS over EUTRAN in case SMSIP is not used.

The signalling on this interface uses SCTP. The SGs interface is defined in TS 23.272 [81] and TS 29.118 [82].

6.4.3.5 Interface between 3GPP MSC Server and MME or SGSN (Sv-interface)

The Sv reference point provides SRVCC support for functions like sending Forward Relocation Message between MME or SGSN and 3GPP MSC Server. This interface is specified in TS 29.280 [91].

6.4.4 Interfaces internal & related to the Evolved Packet Core

6.4.4.1 Interface between MME and HSS (S6a-interface)

This interface is used to exchange the data related to the location of the mobile station and to the management of the subscriber. The main service provided to the mobile subscriber is the capability to transfer packet data within the whole service area. The MME informs the HSS of the location of a mobile station managed by the latter. The HSS sends to the MME all the data needed to support the service to the mobile subscriber. Exchanges of data may occur when the mobile subscriber requires a particular service, when he wants to change some data attached to his subscription or when some parameters of the subscription are modified by administrative means.

Signalling on this interface uses Diameter S6a/S6d Application as specified in TS 29.272 [86].

6.4.4.2 Interface between SGSN and HSS (S6d-interface)

This interface is used to exchange the data related to the location of the mobile station and to the management of the subscriber. The main service provided to the mobile subscriber is the capability to transfer packet data within the whole service area. The SGSN informs the HSS of the location of a mobile station managed by the latter. The HSS sends to the SGSN all the data needed to support the service to the mobile subscriber. Exchanges of data may occur when the mobile subscriber requires a particular service, when he wants to change some data attached to his subscription or when some parameters of the subscription are modified by administrative means.

Signalling on this interface uses Diameter S6a/S6d Application as specified in TS 29.272 [86].

6.4.4.3 Interface between MME and S-GW (S11-interface)

This interface is used to support mobility and bearer management between the MME and S-GW. This interface is specified in TS 29.274 [90].

6.4.4.4 Interface between MME and MME (S10-interface)

This interface is used to support user information transfer and MME relocation support between the MMEs. This interface is specified in TS 29.274 [90].

6.4.4.5 Interface between S-GW and PDN GW (S5 and S8-interface)

These interfaces are between S-GW and PDN GW, provides support for functions for packet data services towards end users during roaming and non-roaming cases (i.e. S8 is the inter PLMN variant of S5). These interfaces are specified in TS 29.274 [90] and TS 29.281 [126] for GTP and TS 29.275 [93] for PMIP.

6.4.4.6 Interface between MME and EIR (S13-interface)

This interface is used between MME and EIR to exchange data, in order that the EIR can verify the status of the IMEI retrieved from the Mobile Station.

Signalling on this interface uses the Diameter S13 Application. in TS 29.272 [86].

6.4.4.7 Interface between MME and SGSN (S3-interface)

This interface enables user and bearer information exchange for inter 3GPP access network mobility in idle and/or active state. This interface is specified in TS 29.274 [90].

6.4.4.8 Interface between S-GW and SGSN (S4-interface)

This interface provides related control and mobility support between GPRS Core and the 3GPP Anchor function of Serving GW. In addition, if Direct Tunnel is not established, it provides the user plane tunnelling. This interface is specified in TS 29.274 [90] and TS 29.281 [126].

6.4.4.9 Interface between S-GW and UTRAN (S12-interface)

Reference point between UTRAN and Serving GW for user plane tunnelling when Direct Tunnel is established. It is based on the Iu-u/Gn-u reference point using the GTP-U protocol as defined between SGSN and UTRAN or respectively between SGSN and GGSN. Usage of S12 is an operator configuration option. This interface is specified in TS 29.281 [126].

6.4.4.10 Interface between Trusted non-3GPP IP Access and S-GW/PDN GW (S2a-interface)

It provides the user plane with related control and mobility support between trusted non 3GPP IP access and the Gateway. This interface is specified in TS 29.275 [93] and TS 24.304 [94] for PMIP and Client Mobile IPv4 FA mode respectively. When GTP is used in S2a, this interface is specified in TS 29.274 [90] for GTP control plane (GTP-C) and in TS 29.281 [126] for GTP user plane (GTP-U).

6.4.4.11 Interface between PDN GW/S-GW and ePDG (S2b-interface)

It provides the user plane with related control and mobility support between ePDG and the Gateway. This interface is specified in TS 29.274 [90] and TS 29.281 [126] for GTP and in TS 29.275 [93] for PMIP.

6.4.4.12 Interface between PDN GW and UE (S2c-interface)

It provides the user plane with related control and mobility support between UE and the Gateway. This reference point is implemented over trusted and/or untrusted non-3GPP Access and/or 3GPP access. This interface is specified in TS 24.303 [95].

6.4.4.13 Interface between PDN GW and 3GPP AAA Server/proxy (S6b-interface)

It is the reference point between PDN GW and 3GPP AAA server/proxy for mobility related authentication and authorization. This reference point may also be used to retrieve and request storage of mobility parameters, such as the PDN GW Identity. This reference point may also be used to retrieve static QoS profile for a UE for non-3GPP access in case dynamic PCC is not supported. This interface is specified in TS 29.273 [96].

6.4.4.14 Interface between Untrusted non-3GPP IP Access and 3GPP AAA Server/proxy (SWa-interface)

It enables support for the Untrusted non-3GPP IP Access with the 3GPP AAA Server/Proxy and transports access authentication, authorization and charging-related information in a secure manner. This interface is specified in TS 29.273 [96].

6.4.4.15 Interface between Trusted non-3GPP IP Access and 3GPP AAA Server/proxy (STa-interface)

It connects the Trusted non-3GPP IP Access with the 3GPP AAA Server/Proxy and transports access authentication, authorization, mobility parameters and charging-related information in a secure manner. This interface is specified in TS 29.273 [96].

6.4.4.16 Interface between 3GPP AAA Server and 3GPP AAA proxy (SWd-interface)

It connects the 3GPP AAA Proxy, possibly via intermediate networks, to the 3GPP AAA Server. This interface is specified in TS 29.273 [96].

6.4.4.17 Interface between ePDG and 3GPP AAA Server/proxy (SWm-interface)

This reference point is located between 3GPP AAA Server/Proxy and ePDG and is used for AAA signalling (transport of mobility parameters, tunnel authentication and authorization data). This reference point also includes the MAG-AAA interface functionality and Mobile IPv6 NAS-AAA interface functionality. This interface is specified in TS 29.273 [96].

6.4.4.18 Interface between ePDG and Untrusted non-3GPP Access (SWn-interface)

This is the reference point between the Untrusted Non-3GPP IP Access and the ePDG. Traffic on this interface for a UE-initiated tunnel has to be forced towards ePDG. This interface is specified in TS 29.273 [96].

6.4.4.19 Interface between ePDG and UE (SWu-interface)

This is the reference point between the UE and the ePDG and supports handling of IPSec tunnels. The functionality of SWu includes UE-initiated tunnel establishment, user data packet transmission within the IPSec tunnel and tear down of the tunnel and support for fast update of IPSec tunnels during handover between two untrusted non-3GPP IP accesses. This interface is specified in TS 24.302 [97].

6.4.4.20 Interface between HSS and 3GPP AAA Server (SWx-interface)

This reference point is located between 3GPP AAA Server and HSS and is used for transport of authentication data. This interface is specified in TS 29.273 [96].

6.4.4.21 Interface between UE and ANDSF (S14-interface)

This reference point is between UE and ANDSF for direct queries via pull mechanism. It enables dynamic provision of information to the UE for Network discovery and selection procedures related to non-3GPP accesses. Push and/or combination of Pull-Push may be supported as well. This interface is specified in TS 24.302 [97].

6.4.4.22 Reference point between HRDP AN and MME (S101-reference point)

The S101 interface supports procedures for Pre-Registration, Session Maintenance and Active handovers between E‑UTRAN and HRPD networks. This is based on tunnelling over S101 signalling of one technology while the UE is in the other technology as specified in TS 23.402 [77]. The HRPD air interface messages tunnelled over S101 in E‑UTRAN to HRPD mobility are defined in 3GPP2 C.S0087 0 [107].

6.4.4.23 Reference point between 3GPP2 1xCS IWS and MME (S102-reference point)

The S102 reference point provides a tunnel between MME and 3GPP2 1xCS IWS to relay 3GPP2 1xCS signalling messages in order to support SRVCC as specified in TS 23.216 [83] and CS Fallback as specified in TS 23.272 [81]. 1x CS signalling messages are those messages that are defined for A21 interface as described in 3GPP2 A.S0008-C [106].

In case of CS Fallback to 1x CS network as specified in TS 23.272 [81], S102 Tunnel Redirection Procedure is used when the UE perform Tracking Area Update with MME change (as specified in TS 23.402 [77] in case of S101 tunnel redirection) while the UE is registered with the 1xRTT CS domain and the S102 session exists between the MME and the 1xCS IWS.

6.4.4.24 Interface between HSGW and S-GW (S103-interface)

The S103 interface between the Serving GW and HRPD PDSN HSGW supports the forwarding of DL data during mobility from E-UTRAN to HRPD as specified in TS 23.402 [77]. Signalling procedures on the S101 interface are used to set up tunnels on the S103 interface.

6.4.4.25 Reference point between UE and CSG List Server (Uh reference point)

This reference point is used to provision the Allowed CSG list and the Operator CSG list subscription information to the mobile station via OMA DM or OTA. This interface is specified in TS 24.285 [117] for OMA DM and in TS 31.102 [118] for OTA.

6.4.4.26 Reference Point between the CSS and the S4-SGSN (S7d Reference Point)

This reference point is used to transfer to the S4-SGSN the CSG subscription information stored in the VPLMN for roaming UEs.

Signalling on this interface uses Diameter S7d Application as specified in TS 29.272 [86].

6.4.4.27 Reference point between the CSS and the MME (S7a reference point)

This reference point is used to transfer to the MME the CSG subscription information stored in the VPLMN for roaming UEs.

Signalling on this interface uses Diameter S7a Application as specified in TS 29.272 [86].

6.4.4.28 Reference point between the MME and the SMS-GMSC/SMS-IWMSC/SMS Router (SGd reference point)

This reference point is used to transfer short messages between the MME and SMS-GMSC, SMS-IWMSC or SMS Router. The details for this reference point are described in TS 23.040 [137] and TS 29.338 [135].

Signalling on this interface uses Diameter SGd Application as specified in TS 29.338 [135].

6.4.4.29 Reference point between the HSS and the SMS-GMSC/SMS-IWMSC/SMS Router (S6c reference point)

This reference point is used to interrogate the HSS of the required subscriber to obtain routing information for a short message directed to that subscriber. The details for this reference point are described in TS 23.040 [137] and TS 29.338 [135].

Signalling on this interface uses Diameter S6c Application as specified in TS 29.338 [135].

6.4.4.30 Reference point between HRPD AN and MME (S121-interface)

The S121 interface supports RIM message transfer between eNodeB and HRPD AN as described in TS 23.402 [77].