The IMS Multimedia Telephony Service should allow multimedia conversational communications between two or more
users. It provides real time bidirectional conversational transfer of speech, video or optionally other types of data.
The IMS Multimedia Telephony communication is point to point between terminals communicating, or a terminal and a
network entity. This communication is usually symmetrical, but in special cases the media components present in each
direction may be different, or they may be the same but with different bit rates and Quality of Service.
An IMS Multimedia Telephony communication can start with only one type of media and additional types of media
may or may not be added by the users as the communication progress. Therefore a particular IMS Multimedia
Telephony communication may consist of only one type of media, e.g. speech.
This TS defines the IMS Multimedia Telephony service and the minimum set of capabilities required to
secure multi-vendor and multi-operator inter-operability for Multimedia Telephony and related Supplementary
full Table of Contents for TS 22.173 Word version: 17.1.0