7.5 Call Clearing for Iu Interface on IP

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

Procedures for Call Clearing where the Iu Interface is on IP are as described in clauses 7.1 to 7.4, with the exception that only the Access side procedures apply and the Release Bearer procedure is not sent. For Iu Interface on IP, the Release Termination procedures for IP are used to clear the MGW termination from the (G)MSC.


Figure 7.9 shows the network model for a network initiated clearing of the mobile call when IP transport is used on the Iu interface. The ‘squared’ line represents the call control signalling. The ‘dotted’ line represents the bearer. The MSC server releases 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 7.9 Network Initiated Call Clearing (Network model)

Figure 7.10 shows the message sequence example for the network initiated clearing of a mobile call when IP transport is used on the Iu Interface. In the example when the call clearing indication is received from the preceding/succeeding node, MSC server indicates that network bearer can be released and to release the network side bearer termination. After the release of the network side bearer termination the MSC server indicates to the preceding/succeeding node that call clearing has been completed. The MSC server initiates call clearing towards the UE and requests release of the radio resource. After the response of the radio resource release is received then the MSC server requests release of the access side bearer termination.

Figure 7.10 Network Initiated Call Clearing (message sequence chart)