Multiparty Multimedia Session Control (mmusic)

Last Modified: 2008-01-07

Additional information is available at tools.ietf.org/wg/mmusic

Chair(s):

Joerg Ott <jo@acm.org>

Jean-Francois Mule <jf.mule@cablelabs.com>

Real-time Applications and Infrastructure Area Director(s):

Jon Peterson <jon.peterson@neustar.biz>

Cullen Jennings <fluffy@cisco.com>

Real-time Applications and Infrastructure Area Advisor:

Cullen Jennings <fluffy@cisco.com>

Mailing Lists:

General Discussion: mmusic@ietf.org
To Subscribe: mmusic-request@ietf.org
In Body: subscribe your_email_address
Archive: http://www.ietf.org/mail-archive/web/mmusic/index.html

Description of 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 deployment. The group is
now focussed on the revisions of these protocols in the light of
implementation experience and additional demands that have arisen
from other WGs (such as AVT, SIP, SIPPING, and MEGACO).

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.
In spite of these, it is widely deployed.

- To support this current deployment, MMUSIC will revise SDP
suitable for publication as a Draft Standard RFC. This will
involve correcting minor bugs and clarifying the current
specification.

- Various extensions to SDP will be pursued to remedy the most
urgent of SDP's shortcomings. These will be limited to use of
SDP in conjunction with connection-oriented media such as TCP
and SCTP, offering support to work with NATs and firewalls
(e.g. via the ICE methodology), and exchange of media session
security keys.

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
families).

To address the more fundamental issues with SDP, a next generation of
SDP, referred to as SDPng, will be needed. An initial proposal is now
available, and will be progressed to Experimental RFC while we gain
experience with implementations. An informational document will be
produced describing how the transition to a new session description
protocol can be managed, to prepare implementors for such a future
change.

MMUSIC will 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.

An Internet Media Guide (IMG) is a collection of multimedia session
descriptions expressed using SDP or some other session description
format. It is used to describe a collection of multimedia sessions
(e.g. television programme schedules). The IMG must be delivered to
a potentially large audience, who use it to join a subset of the
sessions described, and who may need to be notified of changes to the
IMG.

MMUSIC will investigate delivery mechanisms for IMGs, generalizing
our work on session announcement and discovery protocols (SAP, RTSP,
SIP). We will investigate and document requirements for IMG delivery
mechanisms, and identify the requirements that these delivery
mechanisms impose on the session description formats used by the IMG.
We will then work to produce a framework document outlining the use
of (existing) protocols to create an IMG delivery infrastructure.
After successful completion of these initial milestones for IMG
delivery, the MMUSIC working group will decide whether or not MMUSIC
is the proper place to pursue any needed mechanisms for IMGs, and if
so, recharter accordingly

The MMUSIC work items will be pursued in close coordination with other
IETF WGs related to multimedia conferencing and IP telephony (AVT, SIP,
SIPPING, SIMPLE, XCON, MEGACO and, where appropriate, MIDCOM and NSIS).
Where appropriate, new separate working groups may be split off (as has
happened with the SIP WG).

The Working Group is also charged with addressing security issues
related to the protocols it develops.

Goals and Milestones:

Done		Conduct WG Last Call for SAP Internet-Draft
Done		Submit a revised Internet Multimedia Conferencing Architecture I-D.
Done		Submit a revised SIP I-D.
Done		Submit SDP to the IESG for consideration as a Proposed Standard.
Done		Submit SAP Internet-Draft to IESG for publication as an Experimental Protocol.
Done		Conduct WG Last Call for RTSP Internet-Draft.
Done		Submit Internet-Draft on Internet Multimedia Conferencing Architecture.
Done		Submit RTSP to IESG for consideration as a Proposed Standard.
Done		Conduct WG Last Call for SIP Internet-Draft.
Done		Submit SIP Internet-Draft to IESG for consideration as a Proposed Standard.
Done		Conduct WG Last Call for SAP Security Internet-Draft.
Done		Conduct second WG Last Call for SAP.
Done		Submit SAP Internet-Draft to IESG for consideration as a Proposed Standard.
Done		Submit SAP Security Internet-Draft to IESG for consideration as a Proposed Standard.
Done		Submit IPv6 Extensions to SDP for Proposed Standard
Done		Submit SIP's offer/answer use of SDP for Proposed Standard
Done		Submit SDP4NAT for Proposed Standard (Informational?)
Done		Submit SDP source filter extensions for Proposed Standard
Done		Submit draft on SDPng motivations, comparisons with current SDP capabilities. Request charter review on SDPng work from IAB and IESG.
Done		Submit SDP security extension for Proposed Standard
Done		Submit IMG requirements and framework for Informational
Done		Submit revised SDP spec for Proposed (or Draft) Standard
Done		Submit SDP Offer/Answer examples for Informational
Done		Review work on IMGs and update charter accordingly
Done		Submit SDP connection-oriented media draft for Proposed Standard
Done		Submit SDPng transition scenarios for Informational
Nov 2004		Submit SDPng base specification for Experimental
Done		Submit ICE draft for Proposed Standard
Feb 2005		Submit revised RTSP spec for Proposed or Draft Standard (as appropriate)
May 2005		Submit RTSP NAT considerations draft
Done		Submit updated SDP Offer/Answer examples draft for Informational

Internet-Drafts:

Real Time Streaming Protocol 2.0 (RTSP) (488188 bytes)
An Network Address Translator (NAT) Traversal mechanism for media controlled by Real-Time Streaming Protocol (RTSP) (15113 bytes)
Interactive Connectivity Establishment (ICE): A Protocol for Network Address Translator (NAT) Traversal for Offer/Answer Protocols (286365 bytes)
An Extension to the Session Description Protocol (SDP) for Media Loopback (49125 bytes)
Connectivity Preconditions for Session Description Protocol Media Streams (40379 bytes)
TCP Candidates with Interactive Connectivity Establishment (ICE) (45812 bytes)
A Session Description Protocol (SDP) Offer/Answer Mechanism to Enable File Transfer (100949 bytes)
SDP Capability Negotiation (187028 bytes)
SDP media capabilities Negotiation (46867 bytes)
Quality of Service (QoS) Mechanism Selection in the Session Description Protocol (SDP) (19037 bytes)
Source-Specific Media Attributes in the Session Description Protocol (SDP) (44832 bytes)
Signaling media decoding dependency in Session Description Protocol (SDP) (30606 bytes)
SDP: Session Description Protocol (108203 bytes)

Request For Comments:

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