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Multiparty Multimedia Session Control

Document Charter Multiparty Multimedia Session Control WG (mmusic)
Title Multiparty Multimedia Session Control
Last updated 2020-03-25
State Approved
WG State Active
IESG Responsible AD Murray Kucherawy
Charter edit AD Murray Kucherawy
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The Multiparty MUltimedia SessIon Control (MMUSIC) Working Group was 
originally chartered to develop protocols to support Internet 
teleconferencing and multimedia communications. These protocols are now 
reasonably mature, and many have received widespread deployment. 
Currently, the group is focused on using and negotiating media streams 
with the Session Description Protocol (SDP), which is used as a common 
protocol to express media and session descriptions. The group also 
maintains the Real-time Streaming Protocol (RTSP) specifications.

The group has revised these protocols in the light of implementation 
experience and additional demands that have arisen from other WGs (such 
as AVTCORE, CLUE, ICE, and RTCWEB). In particular, the many uses of SDP 
have led to requests for numerous extensions as well as a recognition of 
several limitations in the original protocol design. Today, the SDP 
protocol is widely deployed and continues to see extensions being defined.

The current aims of the working group include the following:

- Provide SDP signaling support for the Interactive Connectivity 
Establishment (ICE) protocol and its extensions. These were originally 
defined in MMUSIC, but are now handled by the ICE WG.
- To support the establishment of multi-party multimedia sessions for 
RTCWEB based implementations, MMUSIC provides SDP signaling support for 
a number of extensions required by RTCWEB. The MMUSIC WG will seek a 
balanced trade-off between general applicability of such extensions 
versus RTCWEB specific usage.
- Various other extensions to SDP may be pursued to remedy the most 
urgent of SDP's shortcomings. These include updates to the SDP 
specification itself and missing IANA registrations.
- With the exception of the items listed above, only extensions within 
the existing SDP framework will be done.
- Maintain the specification of the (revised) Real Time Streaming 
Protocol (RTSP) as needed.

The MMUSIC work items will be pursued in close coordination with other 
IETF WGs including AVTCORE, CLUE, ICE, RTCWEB and SIPCORE, as well as 
others where appropriate.