Structure-Agnostic Time Division Multiplexing (TDM) over Packet (SAToP)
RFC 4553

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>, 
    pwe3 mailing list <pwe3@ietf.org>, 
    pwe3 chair <pwe3-chairs@tools.ietf.org>
Subject: Protocol Action: 'Structure-Agnostic TDM over Packet 
         (SAToP)' to Proposed Standard 

The IESG has approved the following document:

- 'Structure-Agnostic TDM over Packet (SAToP) '
   <draft-ietf-pwe3-satop-06.txt> as a Proposed Standard

This document is the product of the Pseudowire Emulation Edge to Edge 
Working Group. 

The IESG contact persons are Mark Townsley and Jari Arkko.

A URL of this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-ietf-pwe3-satop-06.txt

- Technical Summary

  This document describes a structure agnostic pseudowire
  encapsulation for low-rate TDM (T1, E1, T3, E3) bit-streams.
  This TDM encapsulation disregards any structure that may be
  imposed on these streams, in particular standard TDM
  framing (e.g. as defined in ITU-T Recommendation G.704).

  SAToP satisfies the requirement for "emulation of
  unstructured TDM circuits" as defined in the PWE3 TDM
  Requirements draft, and can furthermore be used for
  structured TDM for those cases wherein the end-points
  need not interpret TDM structure nor participate in the
  TDM signaling.

  The solution presented in this ID conforms to the PWE3
  architecture described in RFC 3985 and satisfies both the
  relevant general requirements put forward in RFC 3916
  requirements for unstructured TDM signals presented in
  RFC4197

  - Working Group Summary

  This draft was the result of several years of continuous
  discussion by a subset of PWE3 WG participants, and is
  supported by the great majority of those involved. The
  only point of disagreement centered on one optional mode,
  namely the "octet-aligned" mode for emulation of
  unstructured T1 circuits. At a late stage one WG participant
  suggested making this mode MANDATORY rather than OPTIONAL,
  but this position did not gain further support.

  - Protocol Quality

  SAToP was adopted by ITU-T SG-13 Question 5 (now
  Question 7), and has been incorporated into ITU-T
  Recommendation Y.1413 under the name “structure agnostic
  transport� (clause 9.1). It has furthermore been reviewed
  by the MFA Forum where it was incorporated into MPLS
  Implementation Agreement 8.0.0, and by the Metro Ethernet
  Forum where it was incorporated into MEF Implementation
  Agreement 8. The universal acceptance of SAToP by all
  SDOs that have reviewed it strongly demonstrates its
  applicability and quality.

  There are at least four independent, interworking
  implementations of this pseudowire type.