This TR defines the IMS Multimedia Telephony service and associated supplementary services for IMS. It aims to take account and build on the IMS capabilities already provided in 3GPP Release 5 and Release 6.
The objective is to define the minimum set of capabilities required in the IP Multimedia Subsystem to secure multivendor and multi-operator inter-operability for the IMS Multimedia Telephony service and related Supplementary Services.
Close cooperation shall be sought with TISPAN. TISPAN requirements, as captured in ETSI TS 181 002, will be taken into account, and referred to where appropriate.
While the user experience for the IMS Multimedia Telephony service is expected to have some similarity to existing telephony services, the richer capabilities of IMS will be exploited.