5.37.9.1 General

This clause describes the procedure to support transferring of media related information (i.e. information related to the media being transmitted, either explicitly provided by the AS or inferred from protocol headers or payload, e.g. PDU Set Information, Data Burst Size, etc.) over N6. Such support is necessary when the end-to-end connection for XR and media traffic between the UE and Application Server is fully encrypted thus UPF not being able to identify, for example, PDU Set Information.

On-path N6 signalling methods are used to transfer media related information over N6 where media related information is sent together with the encrypted payload allowing media related information to be received synchronously with the media packet. The following on-path N6 signalling methods are supported:

• Using Media over QUIC (MoQ), as defined in IETF draft-ietf-moq-transport [201], whose usage is further defined in clause 5.37.9.2.
• Use of connect-UDP for Using Proxying-UDP-in-HTTP, as defined in IETF RFC 9298 [170] and QUIC-Aware Proxy, draft-ietf-masque-quic-proxy [200], whose usage is further defined in clause 5.37.9.3
• Using UDP-Options, as defined in IETF RFC 9868 [202], whose usage is further defined in clause 5.37.9.4.

For all the above listed on-path N6 signalling methods, the following media related information are supported:

• PDU Set Information (as described in clause 5.37.5.2).
• End of Data Burst Indication (as described in clause 5.37.8.3).
• Expedited Transfer Indication (as described in clause 5.37.10).
• Data Burst Size (as described in clause 5.37.10).
• Time to Next Burst (as described in clause 5.37.10).

The mechanisms defined in clause 5.37.9 address only UE to XRM server (AS) communication and do not address UE-UE XRM communications. The mechanisms defined in clause 5.37.9 support only downlink media related information delivery to the UPF.

The media related information is encrypted and integrity protected between the UPF and the AS, as defined in TS 33.501 [29].