- 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.