Section: 20 Usage of Diameter on SGmb interface 20.1 General
Content: Signalling between MBMS GW and BM-SC is exchanged at SGmb reference point. The MBMS GW uses the SGmb interface: - to receive indication of session start, session update and session stop messages, which shall cause the MBMS GW, MME/SGSN and E-UTRAN/UTRAN to set up/tear down the appropriate resources for the service. For further details, see 3GPP TS 23.246[ Multimedia Broadcast/Multicast Service (MBMS); Architecture and functional description ]  [65]; - to enable the BM-SC and MBMS GW to detect an SGmb path failure or the restart of the peer MBMS node. For further details, see 3GPP TS 23.007[ Restoration procedures ]  [104]. - to enable the BM-SC to transfer the M1 interface information of local MBMS information. For further details, see 3GPP TS 23.285[ Architecture enhancements for V2X services ]  [112]. NOTE: The localized MBMS architecture refers to Annex B of 3GPP TS 23.285[ Architecture enhancements for V2X services ]  [112]. The SGmb application is defined as an IETF vendor specific Diameter application, where the vendor is 3GPP. The vendor identifier assigned by IANA to 3GPP (http://www.iana.org/assignments/enterprise-numbers) is 10415. The SGmb application identifier value assigned by IANA is 16777292. The SGmb application identifier value shall be included in the Auth-Application-Id AVP. The BM-SC and the MBMS GW shall advertise the support of the SGmb application by including the value of the application identifier in the Auth-Application-Id AVP and the value of the 3GPP (10415) in the Vendor-Id AVP of the Capabilities-Exchange-Request and Capabilities-Exchange-Answer commands as specified in IETF RFC 6733 [111], i.e. as part of the Vendor-Specific-Application-Id AVP. The Capabilities-Exchange-Request and Capabilities-Exchange-Answer commands are specified in the Diameter Base Protocol.