From: The IESG To: IETF-Announce Message-Id: Date: Tue, 21 Dec 2004 17:46:26 -0500 Cc: mmusic chair , Internet Architecture Board , mmusic mailing list , mmusic chair , RFC Editor Subject: Protocol Action: 'The Alternative Network Address Types Semantics (ANAT) for theSession Description Protocol (SDP) Grouping Framework' to Proposed Standard The IESG has approved the following document: - 'The Alternative Network Address Types Semantics (ANAT) for theSession Description Protocol (SDP) Grouping Framework ' as a Proposed Standard This document is the product of the Multiparty Multimedia Session Control Working Group. The IESG contact persons are Jon Peterson and Allison Mankin. Technical Summary This addition to the Session Description Protocol (SDP) allows an SDP offer to contain more than one network address associated with a single offered media stream. The motivation for this is IPv6 transition - it allows a dual-stack client to offer both an IPv6 and an IPv4 address from which the answerer can choose. It also allows these addresses to be prioritized, so an offerer can indicate that they would prefer to connect via IPv6, if possible. This has significant applicability to the Interactive Connectivity Establishment (ICE) mechanism being developed in MMUSIC. Working Group Summary The MMUSIC working group supported the advancement of this document. A concern was expressed that interaction of other media grouping semantics in SDP was insufficiently specified, but the media grouping framework was authored by some f the same individuals who wrote this document, and they seem to feel that the distinction is clear enough. Protocol Quality This specification was reviewed for the IESG by Jon Peterson.