6.4 Participating MCVideo function transmission control procedures
24.5813GPPMission Critical Video (MCVideo) media plane controlProtocol specificationRelease 18TS
6.4.1 General
Once an on-demand MCVideo session is established or a pre-established session is in use when the participating MCVideo function receives transmission control messages from the transmission participant in the MCVideo client or from the transmission control server in the controlling MCVideo function, the behaviour of the participating MCVideo function is described in the following clauses.
6.4.2 Receive transmission control messages
Upon receiving a transmission control message the participating MCVideo function:
1. shall immediately forward the transmission control message to the transmission control server if the message is received from the transmission participant;
2. if an MBMS subchannel is not used for a transmission in the session the transmission control message is associated with, shall immediately forward the transmission control message to the transmission participant if the message is received from the transmission control server; and
3. if an MBMS subchannel is used for a transmission in the session the transmission control message is associated with:
a. if
i. the transmission control message is not a Transmission Idle message or a Media Transmission Notify message;
ii. the MCVideo client has not reported "listening" status as specified in 3GPP TS 24.281 [2] clause 14.2.3; or
iii. the MCVideo client has reported "not-listening" status as specified in 3GPP TS 24.281 [2] clause 14.2.3 in the latest received MBMS bearer listening status report;
shall immediately forward the transmission control message to the transmission participant; and
b. if
i. the MCVideo client has reported "listening" status as specified in 3GPP TS 24.281 [2] clause 14.2.3 in the latest received MBMS bearer listening status report; and
ii if the transmission control message is the Transmission Idle message or the Media Transmission Notify message,
shall perform actions as specified in clause 10.2.
NOTE: When the Transmit Idle or Media Transmission Notify messages are discarded the messages are sent to the MCVideo clients over the MBMS subchannel allocated for the transmission as specified in clause 10.2.
6.4.3 Receive RTP media packets (R: RTP Media)
Upon receiving RTP media packets the participating MCVideo function:
1. shall immediately forward the RTP media packet to the controlling MCVideo function if the RTP packet is from an MCVideo client; and
2. if an MBMS subchannel is not used for a transmission in the session the RTP media packets are associated with, shall immediately forward the RTP media packets to the MCVideo client if the RTP packet is from the controlling MCVideo function or the non-controlling MCVideo function.
3. if an MBMS subchannel is used for a transmission in the session the RTP media packets are associated with and if RTP media packets are received from the controlling MCVideo function or the non-controlling MCVideo function:
a. if
i. the MCVideo client has not reported "listening" status as specified in 3GPP TS 24.281 [2] clause 14.2.3; or
ii. the MCVideo client has reported "not-listening" status as specified in 3GPP TS 24.281 [2] clause 14.2.3 in the latest received MBMS bearer listening status report,
shall immediately forward the RTP media packets to the MCVideo client; and
b. if the MCVideo client has reported "listening" status as specified in 3GPP TS 24.281 [2] clause 14.2.3 in the latest received MBMS bearer listening status report, shall perform actions as specified in clause 10.2.
6.4.4 Release of session
When the participating function receives an indication from the application and signalling plane that session release is initiated, the participating MCVideo function:
1. shall stop sending transmission control messages towards the transmission participant and the transmission control server; and
2. shall stop sending RTP media packets towards the MCVideo client and towards the controlling MCVideo function.
When the participating MCVideo function receives an indication from the application and signalling plane that the session is released, the participating MCVideo function:
1. in case of a pre-established session, shall perform the actions in clause 9.3.2; and
2. in case of an on-demand session, shall release the media resources associated with the session.