19 Roaming Architecture for Voice over IMS with Local Breakout

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

Based on inter-operator agreement, the roaming architecture for voice over IMS with local breakout procedure may be supported over the II-NNI.

If the roaming architecture for voice over IMS with local breakout procedure is supported, the procedures in 3GPP TS 24.229 [5] shall be applied and the capabilities below shall be provided at the II-NNI.

The "+g.3gpp.trf" header field parameter (defined in 3GPP TS 24.229 [5] clause 7.9A.3) with a TRF address included in a Feature-Caps header field as described in IETF RFC 6809 [143] in the INVITE request or in the UPDATE request and in the 2xx response to the UPDATE request shall be supported at the roaming II-NNI.

The "+g.3gpp.loopback" header field parameter (defined in 3GPP TS 24.229 [5] clause 7.9A.4) with the identity of the caller’s home network included in the Feature-Caps header field as described in IETF RFC 6809 [143] in the INVITE request or in the UPDATE request and in the 2xx response to the UPDATE request shall be supported for the loopback traversal scenario.

The "loopback-indication" header field parameter (defined in 3GPP TS 24.229 [5] clause 7.2A.5) included the P-Charging-Vector header field in 18x and 2xx responses to the INVITE request , in subsequent requests and in responses to subsequent requests shall be supported for the loopback traversal scenario and at the roaming II-NNI.

The procedures in clause 17 shall be supported at the II-NNI.