Section: 17.5.10 MBMS UE Context Modification Procedure
Content: During the multicast MBMS bearer service activation, the MBMS UE Context is stored in the BM-SC. Later, the MBMS UE Context shall be updated when the UE enters a new Routeing Area (RA) served by a new SGSN or the UE is transitioning between UTRAN and A/Gb mode GERAN or vice versa (Inter-system Intra-SGSN change). See 3GPP TS 23.246[ Multimedia Broadcast/Multicast Service (MBMS); Architecture and functional description ]  [65] and 3GPP TS 29.060[ General Packet Radio Service (GPRS); GPRS Tunnelling Protocol (GTP) across the Gn and Gp interface ]  [24]. GGSN shall pass the relevant data via the Gmb interface to enable the BM-SC to update its MBMS UE context accordingly. Figure 35; Modification of an MBMS UE Context in BM-SC 1, On request from SGSN, the MBMS UE Context is updated in the GGSN. 2. The GGSN sends updated MBMS UE Context parameters (RAI, and CGI/SAI as specified in clause 17.6.1) to BM-SC in an AAR message. 3. The BM-SC updates its MBMS UE Context fields and responds with an AAA message. If the GGSN receives new or updated trace information in step 1, then the above procedure may be followed by a Trace Session Activation procedure (see clause 17.5.8) or a Trace Session Deactivation procedure (see clause 17.5.9).