7.3 (G)MSC server Initiated

23.2053GPPBearer-independent circuit-switched core networkRelease 17Stage 2TS

The following clauses describe the additional requirements for (G)MSC server initiated call clearing in the bearer independent CS core network.

7.3.1 GMSC server

7.3.1.1 Call clearing to the destination side

If the call is already established towards the destination, call clearing is performed as described in clause 7.1.1, call clearing to the outgoing side.

7.3.1.2 Call clearing to the originating side

The call clearing to the originating side is performed as described in clause 7.1.1, call clearing to the outgoing side.

7.3.2 MSC server

7.3.2.1 Call clearing to the UE

The call clearing to the UE is performed as described in clause 7.1.2, call clearing to the UE (bullet 1 and bullet 2 in figure 7.6).

7.3.2.2 Call clearing to the network side

If the call is already established towards the network side, the call clearing to the network side is performed as described in clause 7.2.2, call clearing to the network side (bullet 3 in figure 7.6).

7.3.2.3 Example

Figure 7.5 shows the network model for the MSC server initiated clearing of the mobile call. The "squared" line represents the call control signalling. The "dotted" line represents the bearer control signalling (not applicable in A/Gb mode for the A-interface) and the bearer. The MSC server seizes one context with two bearer terminations in the MGW. Bearer termination T1 is used for the bearer towards RNC/BSC and bearer termination T2 is used for the bearer towards succeeding MGW.

Figure 7.5: MSC Server Initiated Call Clearing (Network model)

Figure 7.6 shows the message sequence example for the MSC server initiated clearing of a mobile call. In the example the MSC server initiates call clearing of the network side and the access side. After the call clearing towards the UE and the release of the radio resource have been completed the MSC server requests release of the access side bearer termination. Once the preceding/succeeding node has indicated that call clearing has been completed, the MSC server indicates that the network bearer can be released and to release the network side bearer termination.

Figure 7.6: MSC Server Initiated Call Clearing (message sequence chart)