5.6.17.1 General

Handling of Payload Headers is an optional feature that allows exchange of information in-band in the user plane packets between the application (in the UE or in the application server) and UPF in the 5GS by supporting detection, insertion, replacement, or removal of payload headers of PDUs. Handling of Payload Headers is requested by the AF.

NOTE 1: The Handling of Payload Headers is not limited to the protocol header but can be any field or tag supported by a protocol.

NOTE 2: Handling of Payload Headers is expected to be used instead of Header Enrichment (see clause 5.8.5.6) as it allows more actions than just insertion, supports different protocols and allows the usage of actions in both directions.

The content of this clause applies to non-roaming and to Home Routed roaming scenario, i.e. to cases where the involved entities (AF, PCF, SMF, UPF) belong to the Home PLMN and the AF has an agreement with the Home PLMN.

The PCF controls Handling of Payload Headers in UPF by provisioning Header Handling Control information in the PCC rule. The PCF derives the Header Handling Control information as described in 6.1.3.30 of TS 23.503 [45] based on the AF request and provides it to the SMF in the related PCC rule as described in clause 6.3.1 of TS 23.503 [45]. SMF instructs UPF via N4 interactions by means of FAR (see clause 5.8.5.6).

The UPF performs Handling of Payload Headers and may notify events related to the Handling of Payload Headers to SMF, to NEF/AF or to both as described in clause 5.6.17.2.