B.1 Scope

29.1653GPPInter-IMS Network to Network Interface (NNI)Release 18TS

This annex provides the applicability of SIP header fields in SIP messages over II-NNI by using the methodology of a so-called "dynamic view", as used in IETF RFC 3261 [13] and other SIP related RFCs. This methodology documents the presence of SIP header fields in SIP messages over the II-NNI and also takes into account dynamic conditions, for instance the presence of a SIP header field in a SIP request message as condition for the SIP header field in the corresponding SIP response message.

Specific information about the applicability of SIP header fields in SIP messages in a dynamic view is also provided for cases where an MMTEL supplementary service is supported over the II-NNI between operators.

The applicability of SIP header fields described in this annex is based on the procedures described in 3GPP TS 24.229 [5] and the list of SIP header fields in annex A of 3GPP TS 24.229 [5].