3GPP 23.501 v20.2.0 — the document's own text
5.37.11 Traffic identification and differentiated QoS for multiplexed media flows
Taught in 23. Very fast, very reliable, very picky (The 5G system architecture, in depth).
XR and interactive media services can send data traffic of different media components with different QoS requirements. Several media flows could be multiplexed on the same end-to-end transport layer connection. In order to uniquely identify each media flow, the IP Packet Filter can further include multiplexed media specific (S)RTP Multiplexed Media Identification Information to differentiate the media flow among multiple media flows that share the same transport layer related elements in the packet filter (see clause 5.7.6.2).
The AF may provide individual QoS requirements for each individual RTP media flow within the multiplexed data flows and for the (S)RTCP that controls the (S)RTP transmission, by including the (S)RTP Multiplexed Media Identification Information associated with the individual QoS requirements within the flow description in the "AF session with the required QoS" procedure specified in clauses 4.15.6.6 and 4.15.6.6a of TS 23.502 [3]. The policy control related to multiplexed media flows identification is specified in clause 6.1.3.22 of TS 23.503 [45].
If a UE indicates support of (S)RTP Multiplexed Media Identification Information in the IP packet filter, it shall indicate this to the SMF at PDU Session establishment and the SMF provides this UE capability information to the PCF. The PCF considers such UE capability information when providing the PCC rules to the SMF.
If (S)RTP Multiplexed Media Identification Information is received in the PCC rule, the SMF provides (S)RTP Multiplexed Media Identification Information to the UPF in the corresponding PDR(s) and also to the UE in the QoS Rule if the UE has indicated that it supports (S)RTP Multiplexed Media Identification Information in IP packet filter. If the UE has not indicated so, the SMF shall not provide the (S)RTP Multiplexed Media Identification information in the QoS Rule to the UE. Reflective QoS shall not be applied to SDFs which are identified with (S)RTP Multiplexed Media Identification Information defined in clause 5.7.6.2.