NGN
IMS Based Architecture – Self-SIP in IMS

SIP and SDP as a protocol has been selected to some and IPv6 as the only solution to all of the IP Multimedia Subsystem interfaces.

As shown by the figure below the basic SIP has been selected as the main protocol on the following interfaces:

Eventually there may be differences in the SIP procedures of Gm and Mw reference points. This implies that there is a difference in UNI and NNI interfaces.

The following procedures have been defined for the 3GPP IM subsystem in:

SIP protocol in IMS