The following subclauses specify the procedures for resource management for mission critical services. The procedures are utilised by the following MC services:
The MC service server sets up media bearers and may need to modify the bearers for an already established MC communication.
Media characteristics that may need to be modified include:
activation and deactivation of the bearer;
modification of the QoS characteristics of the bearer (e.g. bearer priority adjustment); and
modification of GBR due to media codec change
The information elements associated to the resources management procedures in this clause are derived from the respective communication setup procedures in TS 23.379, TS 23.281 and TS 23.282.
The procedure defined in this subclause specifies how network resources are requested at session establishment. If concurrent sessions are used the MC service server may utilize the capability of resource sharing specified in TS 23.203. The request for resources is sent to the PCRF on the Rx reference point and includes media type, bandwidth, priority, application identifier and resource sharing information.
The procedure is generic to any type of session establishment that requires requests for network resources.
Procedures in Figure 10.11.2-1 are the signalling procedures for the requesting resource at session establishment.
The procedure defined in this clause specifies how network resources are requested at session establishment from the MC service server. The request for resources is sent to the PCRF via the Rx reference point from the MC service server and includes media type, bandwidth, priority, application identifier and resource sharing information. If concurrent sessions are used, the MC service server may utilize the capability of resource sharing specified in TS 23.203.
For the request of network resources by the MC service server via the Rx reference point, the MC service client provides to the MC service server the final access resource details (e.g. IP addresses and ports) of the MC service client and the media anchoring points.
This procedure is generic to any type of session establishment with the MC service server requesting network resources.
The MC service client sends a session establishment request. The request includes, apart from the SDP offer, access resource details, e.g. IP addresses and ports of the MC service client related to the media session.
The MC service client acknowledges the session establishment to the MC service server. This message contains the final negotiated media access parameters, e.g. IP addresses and ports related to the media anchoring points received in the SDP answer from the SIP core.
To modify unicast media bearers, the MC service server shall send a resource modification request containing the parameters to be modified, using the call control protocol via the SIP core to the UE.
Possible scenarios when this procedure may be used are:
Modify the allocation and retention priority for unicast resources;
Release and resume resources in-between MC service calls when using the chat model; or
Release and resume resources when a UE is able to receive the MC service call over multicast transmission
Releasing resources for the media plane should give the option to allow the SIP session to either be torn down or continue.
Procedures in Figure 10.11.3-1 are the signalling procedures for the modification of a unicast:
Pre-conditions:
MC service server decides to modify the parameters of a unicast bearer (e.g. a request to upgrade the existing MC service call to an MC service emergency or imminent-peril call).
To activate the multicast media bearers the MC service server shall use the Activate MBMS Bearer procedure specified in TS 23.468 with the MC service server performing the GCS AS function. The MC service server shall activate MBMS bearers in broadcast areas where eMBMS capable UEs are or are expected to be located. For that, the MC service server shall use the MBMS SAI(s) and/or cell id(s) information to construct the MBMS broadcast area parameter in the Activate MBMS Bearer procedure.
To deactivate the multicast media bearers the MC service server shall use the Deactivate MBMS Bearer procedure specified in TS 23.468 with the MC service server performing the GCS AS function.
To modify multicast media bearers the MC service server shall use the Modify MBMS Bearer procedure specified in TS 23.468 with the MC service server performing the GCS AS function.