5.25 Support of IPTV (for 5GC)

29.2443GPPInterface between the Control Plane and the User Plane nodesRelease 17TS

IPTV service is defined in clause 4.9.1 of of 3GPP TS 23.316 [51]. Stage 2 procedures to support IPTV service are defined in clauses 4.6 and 7.7.1 of 3GPP TS 23.316 [51].

Support of IPTV service is optional for the SMF and UPF. The following requirements shall apply for IPTV service if the UPF supports the IPTV feature (see clause 8.2.25).

This requires the UPF (PSA) to support:

– terminating and managing IGMP or MLD messages received from the UE;

– acting as a Multicast Router as defined in in IETF RFC 2236 [52] and IETF RFC 3376 [53];

– replicating IP multicast traffic received from the N6 interface over PDU sessions having joined the corresponding IP multicast group;

– notifying the SMF when a PDU session has joined or left a multicast group, if so requested by the SMF.

NOTE: In this specification, "IGMP" refers to IGMPv2 and IGMPv3 and "MLD" refers to MLDv1 and MLDv2, unless specified otherwise.

For a PDU session used for IPTV service, the SMF shall provision the following rules in the UPF to control the UL IGMP/MLD traffic and the DL IP multicast traffic as follows:

– for the control of UL IGMP or MLD traffic:

– a PDR that shall identify IGMPv2 (see IETF RFC 2236 [52]), IGMPv3 (see IETF RFC 4604 [54]), MLD (see IETF RFC 2710 [55]) and/or MLD2 (see IETF RFC 4604 [54]) signalling, i.e.:

– with a PDI containing an SDF filter with a Flow Description identifying packets with IP Protocol number of 2, or with a pre-defined PDR matching the same, for IGMP traffic;

– with a pre-defined PDR matching traffic with IPv6 Next Header type value 58 and ICMP Field Type value 131 or 143, for MLD traffic.

– this PDR may also contain IP Multicast Addressing Info IE(s) identifying (ranges of) IP multicast group(s); if no IP Multicast Addressing Info IE is included, the PDR is meant to match any IP multicast group.

– an associated FAR containing the Apply Action IE with the IPMA (IP Multicast Accept) or the IPMD (IP Multicast Deny) flag set in order to request the UPF to accept or deny the UE requests to join the corresponding IP multicast group(s);

– for the control of DL IP multicast traffic

– a PDR including IP Multicast Addressing Info IE(s), identifying (ranges of) IP multicast addresses (DL IP multicast flows) or indicating any IP multicast address by the A (Any) flag set to "1";

– an associated FAR containing the Apply Action IE set to forward or buffer the packets, and in the former case with the Outer Header Creation IE set to add the remote N3 or N9 GTP-U tunnel IP address and TEID related with the PDU session;

– optionally an associated QER indicating the QoS to use for the PDU session for the IP Multicast traffic that has been replicated.

The UPF shall add or remove the PDU session to/from the DL replication tree associated with an IP Multicast flow, when the UE request to join the IP Multicast flow is accepted or when the UE requests to leave the IP Multicast flow. When receiving downlink IP multicast traffic, the UPF shall replicate the traffic towards each PDU session that has joined the corresponding IP multicast group and that is provisioned with a DL PDR enabling the forwarding of the corresponding IP multicast traffic.

Additionally, the SMF may provision a URR, associated with the UL PDR controlling the IGMP or MLD traffic, with a Reporting trigger set to "IP multicast join/leave" to request the UPF to report to the SMF when it adds or remove the PDU session to/from the DL replication tree associated with an IP Multicast flow. Corresponding reports shall contain the Multicast IP address of the DL multicast flow and, if available, the Source specific IP address(es) of the DL IP multicast flow.