The procedure in this sub clause specify how request for resource for floor control (or transmission control in MCVideo and MCData) and for the media plane can be handled independently. This procedure utilizes the Rx reference point both between from the MC service server to the PCRF and from the SIP core to the PCRF.
Resource for the transmission control are requested at session establishment, in this case the IMS standard procedures as specified in TS 23.228
are used. The session description shall in this procedure include bandwidth information applicable for the transmission control traffic requirement. At group call setup the request for resources for the media plane is triggered. This request is sent directly from the MC service server to the PCRF.
The procedure is optional and is suitable when the procedures for pre-established sessions are used, it may also be used to setup and tear down the media plane used by between consecutive group calls in one communication session using the chat call model.
The MC service client sends a request for group affiliation.
The MC service client sends a request to the MC service server for establishment of a communication session.
The MC service server answer the session establishment request and adjust the bandwidth information in the session description. The requested bandwidth shall be minimized to cover the bandwidth requirements for floor control signaling (or transmission control for MCVideo or MCData).
The SIP core request resources towards the PCRF according to the session establishment request.5. The session establishment request is completed and a response is sent towards the MC service client.
The MC service client sends a cell setup message according to existing procedures.
The MC service server sends a request for resources for the media plane to PCRF, and the media plane is by that established. This request includes media description relevant for the media plane.
Group call is ongoing on the group communication session.
The MC service serve sends a release of media resources to PCRF, and the media plane is by that terminated.