IMS(IP Multimedia Subsystem)Edit
IMS is currently in development and testing phases, and was originally developed by 3GPP as an architecture for Mobile Networks.
IMS describes a full architecture that uses IP technologies to transport all traffic (both Voice and Data). It tries to re-use existing protocols defined by IETF and other standards bodies instead of re-inventing the wheel. Some of the protocols it reuses are SIP, MEGACO/H.248, SIGTRAN and DIAMETER.
TISPAN reuses as much as possible from the IMS architecture and complements it with the required elements to serve fixed/wireless networks.
The work developed by TISPAN is then feed back into IMS.