Multiparty Multimedia Session Control (mmusic) ---------------------------------------------- Charter Last Modified: 2006-07-05 Current Status: Active Working Group Chair(s): Colin Perkins Joerg Ott Jean-Francois Mule Real-time Applications and Infrastructure Area Director(s): Jon Peterson Cullen Jennings Real-time Applications and Infrastructure Area Advisor: Cullen Jennings 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 Aug 2004 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 Nov 2004 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: Posted Revised I-D Title ------ ------- -------------------------------------------- Feb 2002 Jun 2007 Real Time Streaming Protocol 2.0 (RTSP) Oct 2003 Jun 2007 Interactive Connectivity Establishment (ICE): A Protocol for Network Address Translator (NAT) Traversal for Offer/Answer Protocols Dec 2004 Apr 2007 An Extension to the Session Description Protocol (SDP) for Media Loopback Feb 2005 Oct 2006 Security Preconditions for Session Description Protocol (SDP) Media Streams Mar 2006 Mar 2007 TCP Candidates with Interactive Connectivity Establishment (ICE Dec 2006 Mar 2007 SDP Capability Negotiation: Requirements and Review of Existing Work Dec 2006 Jun 2007 A Session Description Protocol (SDP) Offer/Answer Mechanism to Enable File Transfer Jan 2007 Mar 2007 SDP Capability Negotiation Feb 2007 Feb 2007 SDP media capabilities Negotiation Request For Comments: RFC Stat Published Title ------- -- ----------- ------------------------------------ RFC2326 PS Apr 1998 Real Time Streaming Protocol (RTSP) RFC2327 PS Apr 1998 SDP: Session Description Protocol RFC2543 PS Mar 1999 SIP: Session Initiation Protocol RFC2974 E Oct 2000 Session Announcement Protocol RFC3108 PS May 2001 Conventions for the use of the Session Description Protocol (SDP)for ATM Bearer Connections RFC3259 I May 2002 A Message Bus for Local Coordiantion RFC3266 PS Jul 2002 Support for IPv6 in SDP RFC3264 PS Jul 2002 An Offer/Answer Model with SDP RFC3388 PS Dec 2002 Grouping of media lines in Session Description Protocol SDP RFC3524 PS Apr 2003 Mapping of Media Streams to Resource Reservation Flows RFC3605Standard Oct 2003 RTCP attribute in SDP RFC3890Standard Sep 2004 A Transport Independent Bandwidth Modifier for the Session Description Protocol (SDP) RFC4091Standard Jun 2005 The Alternative Network Address Types (ANAT) Semantics for the Session Description Protocol (SDP) Grouping Framework RFC4145Standard Sep 2005 TCP-Based Media Transport in the Session Description Protocol (SDP) RFC4317 I Dec 2005 Session Description Protocol (SDP) Offer/Answer Examples RFC4435 I Apr 2006 A Framework for the Usage of Internet Media Guides (IMGs) RFC4473 I May 2006 Requirements for Internet Media Guides (IMGs) RFC4566 PS Jul 2006 SDP: Session Description Protocol RFC4572 PS Jul 2006 Connection-Oriented Media Transport over the Transport Layer Security (TLS) Protocol in the Session Description Protocol (SDP) RFC4570 PS Jul 2006 Session Description Protocol (SDP) Source Filters RFC4568 PS Jul 2006 Session Description Protocol Security Descriptions for Media Streams RFC4567 PS Jul 2006 Key Management Extensions for Session Description Protocol (SDP) and Real Time Streaming Protocol (RTSP) RFC4574 PS Aug 2006 The Session Description Protocol (SDP) Label Attribute RFC4583 PS Nov 2006 Session Description Protocol (SDP) Format for Binary Floor Control Protocol (BFCP) Streams RFC4756 PS Nov 2006 Forward Error Correction Grouping Semantics in Session Description Protocol RFC4796 PS Feb 2007 The Session Description Protocol (SDP) Content Attribute