The IESG has approved the Internet-Draft 'Grouping of m lines in SDP' <draft-ietf-mmusic-fid-06.txt> as a Proposed Standard. This document is the product of the Multiparty Multimedia Session Control Working Group. The IESG contact persons are Allison Mankin and Scott Bradner. Technical Summary A Session Description Protocol (SDP) description typically contains a number (one or more) media lines - which are commonly known as "m" lines. When a session description contains more than one "m" line, SDP does not provide any means to express a particular relationship between them. When an application receives an SDP session description with more than one "m" line it is currently up to the application to figure out what to do with them. SDP currently does not carry any information about grouping media streams. While in some environments this information can be carried out of band, it would be desirable to have extensions to SDP that allowed the sender to express how different media streams within a session description relate to each other. This document defines such extensions. Specifically, this document defines two new SDP attributes: "group" and "mid". They allow a sender to group together several "m" lines for two different purposes: for lip synchronization and for receiving media from a single flow (several media streams), encoded in different formats during a particular session, through different ports and host interfaces. The further handling of the media for the grouping are then handling by the application, and the grouping in the SDP description by this extension is a convenince. Working Group Summary The mmusic working group supported the publication of this document with no controversy. Protocol Quality This document was reviewed for the IESG by Allison Mankin
