TISPAN; IP Multimedia Subsystem (IMS); Functional architecture
The present document describes the IP Multimedia Subsystem (IMS) core component of the TISPAN NGN functional architecture and its relationships to other subsystems and components.
Use of IMS functional entities in support of transit scenarios is incompletely described. Completion of this description is dependent on ongoing work in 3GPP.
NOTE: 3GPP SA2 is working on a solution for IMS transit, according to an agreement between TISPAN and 3GPP. When ready, that solution will replace any solution documented by TISPAN in case of discrepancy. The affected IMS functional entities, and the way they perform transit routing, may also be different in the SA2 solution than what is documented in the present document. The SA2 solution will be added to the TISPAN Release-1 documentation.