The Early Session Disposition Type for the Session Initiation Protocol (SIP)
RFC 3959

Approval announcement
Draft of message to be sent after approval:

From: The IESG <iesg-secretary@ietf.org>
To: IETF-Announce <ietf-announce@ietf.org>
Cc: Internet Architecture Board <iab@iab.org>,
    RFC Editor <rfc-editor@rfc-editor.org>, 
    sipping mailing list <sipping@ietf.org>, 
    sipping chair <sipping-chairs@tools.ietf.org>
Subject: Protocol Action: 'The Early Session Disposition Type 
         for the Session Initiation Protocol (SIP)' to Proposed Standard 

The IESG has approved the following documents:

- 'The Early Session Disposition Type for the Session Initiation Protocol 
   (SIP) '
   <draft-ietf-sipping-early-disposition-04.txt> as a Proposed Standard
- 'Early Media and Ringing Tone Generation in the Session Initiation 
   Protocol (SIP) '
   <draft-ietf-sipping-early-media-03.txt> as an Informational RFC

These documents are products of the Session Initiation Proposal 
Investigation Working Group. 

The IESG contact persons are Allison Mankin and Jon Peterson.

A URL of this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-ietf-sipping-early-disposition-04.txt

Technical Summary
 
   The Early Session Disposition Type for the Session Initiation Protocol :
   
  This document defines a new disposition type (early-session) for the
   Content-Disposition header field in SIP. The treatment of
   "early-session" bodies is similar to the treatment of "session"
   bodies. That is, they follow the offer/answer model. Their only
   difference is that session descriptions whose disposition type is
   "early-session" are used to establish early media sessions within
   early dialogs, as opposed to regular sessions within regular dialogs.

  Early media refers to media (e.g., audio and video) that is exchanged
   before a particular session is accepted by the called user. Within a
   dialog, early media occurs from the moment the initial INVITE is sent
   until the callee generates a final response. It may be unidirectional or
   bi-directional, and can be generated by the caller, the callee, or
   both. Typical examples of early media generated by the callee are
   ringing tone and announcements (e.g., queuing status.) Early media
   generated by the caller typically consists of voice commands or DTMF
   tones that drive interactive voice servers.

 Early Media and Ringing Tone Generation in the Session Initiation Protocol

   This documents describes some models for early media handling.

Working Group Summary
 
   The design choice of using an early-session Content-Disposition
    header field to parallel the session header field was not contentious.
    The working group had a very long process of coming to consensus
    on early media handling, given that there are real requirements for
    it, but potential abuses as well.  The Informational document's models
    summarize the consensus that the group could reach.  
 
Protocol Quality

Allison Mankin reviewed the documents for the IESG.


RFC Editor Notes:

  In both documents:

   Expand the first appearance of UAC to User Agent Client (UAC),
   the first appearance of UAC to User Agent Server (UAS), and the
   first appearance of UA to User Agent (UA).

   Expand first instance of SRTP to Secure Realtime Transport Protocol (SRTP)
   Expand first instance of STUN to Simple Traversal of the UDP Protocol through
NAT (STUN)

  In draft-ietf-sipping-early-disposition:

   Expand the first instance of PSTN to Public Switched Telephone Network 
(PSTN)
   Expand PIN to Personal Identification Number (PIN)
   Expand GUI to Graphical User Interface (GUI)

  In draft-ietf-sipping-early-media:

   Expand ICE to Interactive Connectivity Establishment (ICE)
   Expand SRTP to Secure Realtime Transport Protocol (SRTP)

  OLD:
   or DTMF tones to drive IVRs

  NEW:
   or dual tone multi-frequency (DTMF) tone to drive interactive
   voice response (IVR) systems

  OLD:
   A POTS-like SIP UA

  NEW:
   A POTS ("Plain Old Telephone Service")-like SIP User Agent (UA)

  OLD:
   3G IMS

  NEW:
   3GPP IMS (Third Generation Partnership Project Internet
   Multimedia System)