13.20.6 Voice group call and voice broadcast services with AoIP

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

Figure 13.20.6/1 shows the example message flow for the establishment of a VGCS call when AoIP is used with two cells and when the talker is located in cell1 and the Talker is on a dedicated channel. Figure 13.20.5/1 shows the applicable possible network model of an anchor MSC for a voice group call when the talker is on the dedicated channel.

Before the MSC server sends the Assignment Request to the BSC, the MSC server requests the MGW to reserve an RTP bearer termination using the Reserve RTP Connection Point procedure.

The MSC server requests the MGW to reserve an IP Address and UDP Port and also may indicate that the IP interface type is for AoIP. The MGW reserves the RTP termination and indicates the IP address and UDP port number to the MSC server.

The MSC server then requests access bearer assignment using the provided IP address and UDP Port.

When the MSC server receives the BSSMAP ASSIGNMENT COMPLETE message, it shall send the BSC IP address and UDP Port to the MGW Access bearer termination using the Configure RTP Connection Point procedure.

Figure 13.20.6/1: Message sequence chart for a voice group call with AoIP when talker is on dedicated channel