Content for TS 23.246 Word version: 18.0.0
8.10 Inter SGSN Routeing Area Update p. 59
This procedure describes the handling of MBMS bearer services when an MBMS UE performs a Routeing Area Update and the serving SGSN changes. It is based on the Inter SGSN Routeing Area Update procedure specified in TS 23.060. The procedure is performed regardless whether MBMS sessions are ongoing or not. The handling of any PDP contexts established by the UE is not changed compared to the procedure without MBMS. The procedure described below does not show all details of the Routeing Area update procedure. Only for the MBMS specific additions the steps are described.
Step 2.
An SGSN supporting MBMS indicates its MBMS support in the SGSN Context Request message. If the SGSN indicates that it supports MBMS, the old SGSN includes the transfer of the MBMS UE Context(s) in the SGSN Context Response message.
Step 7.
For the MBMS UE context(s) received in step 2) the new SGSN sends Update MBMS UE Context Request (Serving network identity, MS Time Zone, CGI/SAI, RAT Type, Additional MBMS Trace Info) to the GGSNs concerned. The GGSNs update their MBMS UE Context fields and return Update MBMS UE Context Response.
Step 8.
The GGSN sends Update MBMS UE Context Request (RAI) to the BM-SC. The inclusion of CGI/SAI shall be according rules detailed in clause 15.1.1a in TS 23.060. The BM-SC updates its MBMS UE Context fields and return Update MBMS UE Context Response.
Step 9.
If the GGSN receives new or updated Additional MBMS Trace Info from the new SGSN, the GGSN sends an Activate Trace (Additional MBMS Trace Info) message to the BM-SC.
Step 14.
In case the new SGSN indicated no MBMS support in step 2) the old SGSN deactivates all MBMS UE context(s) of the UE in SGSN, GGSN and BM-SC by initiating deactivation procedure(s) as described in clause 8.7 "MBMS Multicast Service Deactivation".
Step 15.
If the old SGSN does not have any more MBMS UE Contexts for the MBMS bearer service(s) and the "list of downstream nodes" in the corresponding MBMS Bearer Context is empty, the SGSN initiates the MBMS De-Registration Procedure. See clause "8.6 MBMS De-Registration Procedure".
Step 16.
In case the new SGSN indicated MBMS support in step 2), the new SGSN verifies for each MBMS UE Context received whether it has a corresponding MBMS Bearer Context. For each MBMS Bearer Context that the SGSN does not already have, the SGSN creates an MBMS Bearer Context (in "Standby" state) and initiates the MBMS Registration Procedure towards the GGSN. See clause 8.4 "MBMS Registration Procedure".
Step 17.
An SGSN without MBMS support does not indicate MBMS feature support in the Routing Area Update Accept message. On the other hand if the SGSN supports MBMS, the Routing Area Update Accept indicates to the UE that the network supports MBMS.
8.10a Inter-system Intra-SGSN change p. 60
For an MBMS UE transitioning between UTRAN and A/Gb mode GERAN, the procedures are the same as the Iu mode to A/Gb mode Intra SGSN Change and A/Gb mode to Iu mode Intra SGSN Change procedures specified in TS 23.060.
Furthermore, the same considerations on Radio Access Technology changes apply as specified in the impacts of applying flow based charging specified in TS 23.060, i.e. the SGSN shall send an Update MBMS UE Context Request to the GGSN. Subsequently the GGSN shall send an Update MBMS UE Context Request to the BM-SC as described in the Inter SGSN Routeing Area Update procedure in clause 8.10.
