Study on Indication of Network to Network Interface (NNI) routeing scenarios in Session Initiation Protocol (SIP) requests in the IP Multimedia Subsystem (IMS)
The present document provides a study of the IMS impacts for providing a solution for determination of Inter‑IMS Network to Network Interface (II-NNI) traversal scenario type. The document describes and analyses different II‑NNI traversal scenarios. The present document describes requirements and investigates the implementation options to fulfil requirements for determination of II-NNI traversal scenario type.
Examples of scenarios to study are:
- the visited to home scenario;
- the home to visited scenario;
- the loopback scenario;
- the invocation of MRB/MRF in visited network from an AS in home network scenario; and
- a request sent from the home network on the originating side to the home network on the terminating side.
The present document includes the study of the existing protocol mechanism and new protocol mechanism for further evaluation what is needed to identify a particular II-NNI traversal scenario type.
The study also considers existing deployments.
The present document analyses and evaluates different solutions.