7.2 User Initiated

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

The user initiated call clearing shall be performed in accordance with 3GPP TS 23.108 [18]. The following clauses describe the additional requirements for the bearer independent CS core network.

7.2.1 Void

7.2.2 MSC server

7.2.2.1 all clearing from the UE

The UE initiated call clearing is performed and the release of the associated radio resources is performed as described in 3GPP TS 23.108 [18]. Once the call clearing and the associated radio resources release have been completed, the MSC server releases any MGW allocated resources for the access side. If any resources were seized in the MGW the MSC server uses the Release Termination procedure to requests the MGW to remove the access side bearer termination (bullet 1 or bullet 2 in figure 7.4).

7.2.2.2 Call clearing to the network side

The MSC server sends the Release message to the preceding/succeeding node. Once the preceding/succeeding node has sent the Release Complete, the MSC server releases any MGW allocated resources for the network side. If any resources were seized in the MGW server shall use the Release Bearer and Release Termination procedures to indicate to the MGW to remove the network side bearer termination and that the bearer can be released towards the preceding/succeeding MGW (bullet 3 in figure 7.4).

7.2.2.3 Example

Figure 7.3 shows the network model for a user initiated clearing of a 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 7.3: User Initiated Call Clearing (Network model)

Figure 7.4 shows the message sequence example for the user initiated clearing of a mobile call. In the example the UE initiates call clearing towards the MSC server and the MSC server requests release of the radio resource. After the response of the radio resource release is received the MSC server requests the release of the access side bearer termination. The MSC server initiates call clearing towards the preceding/succeeding node. 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 7.4: User Initiated Call Clearing (message sequence chart)