Multiparty Multimedia Session Control (mmusic)

WG Name Multiparty Multimedia Session Control
Acronym mmusic
Area Applications and Real-Time Area (art)
State Active
Charter charter-ietf-mmusic-03 Approved
Personnel Chairs Flemming Andreasen
Ari Keranen
Area Director Ben Campbell
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Charter for Working Group

The Multiparty MUltimedia SessIon Control (MMUSIC) Working Group was
chartered to develop protocols to support Internet teleconferencing and
multimedia communications. These protocols are now reasonably mature,
and many have received widespread deployments. The group has revised
some of these protocols in the light of implementation experience and
additional demands that have arisen from other WGs (such as AVT, SIP,
and SIPPING). It is focused on using and negotiating mechanisms such
STUN and TURN in order to enable media sessions to traverse Network
Address Translators NATs, and on new means to exchange SDP capabilities.

Multimedia communications protocols use a common platform to express
media and session descriptions: the Session Description Protocol, SDP.
The many uses of SDP have led to (requests for) numerous extensions and
have led to recognition of several flaws in the protocol design, some of
which were addressed in the revision of SDP. In spite of these, it is
widely deployed.

The current aims of the working group include the following:

- To support the establishment of multi-party multimedia sessions across
NATs, MMUSIC will define an Internet Connectivity Establishment
protocol (ICE). This will define several SDP extensions to work with
NATs for media sessions carried over both UDP and TCP.

- Various extensions to SDP will be pursued to remedy the most urgent of
SDP's shortcomings. These will be limited and include adding support
for limited but generic capability negotiations in SDP, defining the
means to select QoS mechanisms to use for a particular media stream,
enabling file transfer via the SDP Offer/Answer model, and support
media loopback.

With the exception of these specific items, only extensions within the
existing SDP framework will be done (e.g. registering new codecs and
defining parameters for them, extending SDP to include new address

- to maintain and revise the specification of the Real Time Streaming
Protocol (RTSP), including fixes and clarifications based on
implementation experience. The revised RTSP specification will be
re-issued as a Proposed Standard RFC. We will also document how RTSP
can be used in the presence of NAT boxes.

The MMUSIC work items will be pursued in close coordination with other
IETF WGs including AVT, SIP, SIPPING, SIMPLE, XCON, and BEHAVE, as well
as others where appropriate such as NSIS.


Date Milestone
Jun 2016 Using the SDP Offer/Answer Mechanism for DTLS
Jan 2016 Submit Using Simulcast in SDP and RTP Sessions as Proposed Standard
Dec 2015 Submit SDP Negotiation of DataChannel sub-protocols as Proposed Standard
Sep 2015 Submit IANA registrations of SDP 'proto' attribute for transporting RTP Media over TCP under various RTP profiles as Proposed Standard
Jun 2015 Submit Dual-stack Fairness with ICE as Proposed Standard
Apr 2015 Submit a revision of ICE (RFC 5245) as Proposed Standard
Mar 2015 Submit revised SDP specification to IETF as Proposed Standard
Mar 2015 Submit SDP extensions to classify traffic as Proposed Standard
Feb 2015 Submit SIP usage for Trickle ICE as Proposed Standard
Jan 2015 Submit Trickle ICE as Proposed Standard
Jan 2015 Submit SCTP-Based Media Transport in SDP as Proposed Standard.
Dec 2014 Submit a framework for SDP attributes when multiplexing as Proposed Standard
Dec 2014 Submit SDP extension for cross session stream identification as Proposed Standard
Nov 2014 Submit SDP extensions to negotiate multiplexed media streams as Proposed Standard
Done Submit UDPTL over DTLS as Proposed Standard
Done Submit a document describing current practices in hosted NAT traversal as Informational
Done Submit SDP considerations for G.723 Annex A and G.729 Annex B as Proposed Standard
Done Submit RTSP NAT considerations draft as a Proposed Standard
Done Submit SDP extensions for duplicated streams as Proposed Standard