Annex W UDP-Option carrying media related information over UDP tunnel

When the DL traffic is end-to end encrypted and transported from the AS proxy through a UDP tunnel established using connect-udp between the AS proxy and the PSA UPF as described in clause 5.37.9.2, the AS proxy generates a XRM packet which inner UDP datagram contains the DL UDP media packets, i.e. QUIC packet between AS proxy and UE and the outer UDP datagram between AS proxy and UPF contains UDP-Option carrying encrypted media related information. Figure W-1 shows XRM packet structure.

After the UPF establishes a QUIC connection to the AS proxy using connect-udp according to clause 5.37.9.2, the AS proxy and the PSA UPF negotiates security keys using connect-udp upgrade token in tunnelled mode. Then the AS proxy encodes media related information into the UDP-Option in outer UDP datagram and uses security keys for encrypting media related information carried in the UDP-Option.