Introduction

26.1143GPPIP Multimedia Subsystem (IMS)Media handling and interactionMultimedia telephonyRelease 18TS

Multimedia Telephony Service for IMS (MTSI), here also referred to as Multimedia Telephony, is a standardized IMS telephony service that builds on the IMS capabilities to establish multimedia communications between terminals within and in-between operator networks. The terminals connect to the IMS using either a fixed access network or a 3GPP access network.

The objective of defining a service is to specify the minimum set of capabilities required in the IP Multimedia Subsystem to secure multi-vendor and multi-operator inter-operability for Multimedia Telephony and related Supplementary Services. The objective also includes defining procedures for inter-working between different clients and networks.

The user experience of multimedia telephony is expected to be equivalent to or better than corresponding circuit-switched telephony services. Multimedia telephony also exploits the richer capabilities of IMS. In particular, multiple media components can be used and dynamically added or dropped during a session.