17 Bearer Redirect

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

The BICC [22] Bearer Redirect mechanism may be used for optimising the bearer path when an endpoint of a call changes due to the operation of an application layer service.

17.1 Example of use of Bearer Redirect with Call Forwarding on No Reply (CFNRy)

Figure 17.1A: Before CFNRy (Network model)

Figure 17.1B: CFNRy and Bearer Redirect (Network model)

Figure 17.2 shows the message sequence example for the call forwarding on no reply with Bearer Redirect. In the example, after the call and the bearer towards the access have been released MSC server A requests the MGW A to remove the bearer termination for the served mobile subscriber. MSC server A requests the GMSC server to redirect the bearer to the forwarded to subscriber (interactions towards the access are not shown), using MSC server A as a call control anchor. Once the bearer towards MGW B is established the GMSC server instructs MGW G to connect the incoming bearer to the new bearer (towards MGW B) and informs MSC server A. Once informed that the new bearer has been established MSC server A instructs the GMSC server to removes the old bearer termination (towards MGW A).

Figure 17.2: Information flow for CFNRy with Bearer Redirect (message sequence chart)