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[802SEC] FW: [New-work] WG Review: Recharter of Pseudo Wire Emulation Edge toEdge (pwe3)

802 WG Chairs,

This announcement may be of interest to members of your working group.
Please forward to them if you feel it is appropriate.


-----Original Message-----
From: [] On
Behalf Of The IESG
Sent: Wednesday, December 21, 2005 6:45 AM
Subject: [New-work] WG Review: Recharter of Pseudo Wire Emulation Edge
toEdge (pwe3) 

A modified charter has been submitted for the Pseudo Wire Emulation Edge
to Edge (pwe3) working group in the Internet Area of the IETF. The IESG
has not made any determination as yet.  The modified charter is provided
below for informational purposes only. Please send your comments to the
IESG mailing list ( by December 28th.


Pseudo Wire Emulation Edge to Edge (pwe3)

Current Status: Active Working Group

Stewart Bryant <>
Danny McPherson <>

Internet Area Director(s):
Mark Townsley <>
Margaret Wasserman <>

Internet Area Advisor:
Mark Townsley <>

Matthew Bocci <>

Mailing Lists:
General Discussion:
To Subscribe:
In Body: subscribe your_email_address

Description of Working Group:

Network transport service providers and their users are seeking to
rationalize their networks by migrating their existing services and
platforms onto IP or MPLS enabled IP packet switched networks (PSN).
This migration requires communications services that can emulate the
essential properties of traditional communications links over a PSN.

Pseudowire Emulation Edge to Edge (PWE3) will specify the encapsulation,
transport, control, management, interworking and security of services
emulated over IETF specified PSNs.

A pseudowire emulates a point-to-point link, and provides a single
service which is perceived by its user as an unshared link or circuit of
the chosen service. It is not intended that an emulated service will be
indistinguishable from the service that is being emulated. The emulation
need only be sufficient for the satisfactory operation of the service.
Emulation necessarily involves a degree of cost-performance trade-off.
In some cases it may be necessary to design more than one emulation
mechanism in order to resolve these design conflicts. All emulated
service definitions must include an applicability statement describing
the faithfulness of the emulation. Switching, multiplexing, modification
or other operation on the traditional service, unless required as part
of the emulation, is out of the scope of the PWE3 WG.

PWE3 will make use of existing IETF specified mechanisms unless there
are technical reasons why the existing mechanisms are insufficient or

PWE3 operates "edge to edge" and will not exert control on the
underlying PSN, other than to use any existing QoS or path control
mechanism to provide the required connectivity between the two endpoints
of the PW.

PWE3 will investigate mechanisms necessary to perform clock recovery and
other real-time signaling functions. This work will be coordinated with
the AVT WG and RTP will be used where appropriate.

A PW operating over a shared PSN does not necessarily have the same
intrinsic security as a dedicated, purpose built, network. In some cases
this is satisfactory, while in other cases it will be necessary to
enhance the security of the PW to emulate the intrinsic security of the
emulated service.
PW specifications MUST include a description of how they are to be
operated over a shared PSN with adequate security.

Whilst a service provider may traffic engineer their network in such a
way that PW traffic will not cause significant congestion, a PW deployed
by an end-user may cause congestion of the underlying PSN. Suitable
congestion avoidance mechanisms are therefore needed to protect the
Internet from the unconstrained deployment of PWs.

PWE3 will work closely with the L2VPN WG to ensure a clear demarcation
is defined for where PWE3 stops and L2VPN starts.
PWE3 will coordinate very closely with any WG that is responsible for
protocols which PWE3 intends to extend (e.g., the MPLS WG for LDP), as
well as foster interaction with WGs that intend to extend PWE3

WG Objectives:

Specify the following PW types:

Ethernet, Frame Relay, PPP, HDLC, ATM, low-rate TDM, SONET/SDH and Fibre

PWE3 will specify a PW type for the special case where the access
service payloads at both ends are known to consist entirely of IP
packets. PWE3 will not specify mechanisms by which a PW connects two
different access services.

Specify the control and management functions of chartered PW types, to
include PW setup, configuration, maintenance and tear-down. The PWE3 WG
will do this in its entirety for MPLS PSNs, and the L2TPEXT WG will
develop the L2TP specifics for L2TPv3-based PWs.

Specify Operations and Management (OAM) mechanisms for all PW types,
suitable for operation over both IP/L2TPv3 and MPLS PSNs, and capable of
providing the necessary interworking with the OAM mechanisms of the
emulated service.

Further enhance PW specifications to enable more transparent emulation
when necessary, for example the retention of FCS across a PW.

Define a mechanism for MPLS PWs that provides interoperability with
currently deployed equal cost multiple path (ECMP) algorithms such that
packets for a given PW follow the same path through an MPLS PSN.

Define requirements for and mechanisms to provide interconnection of PWs
(to include inter-domain PWs).

Define requirements for and mechanisms to provide protection and
restoration of PWs.

Goals and Milestones:

Done PWE3 WG started, organize editing teams.
Done Hold interim meeting, including discussion of priority of
service-specific documents and consider pruning some deliverables Done
Accept drafts of service-specific documents as WG items Done
Requirements Document Last Call Done TDM Circuit Documents Last Call
Done ATM Documents Last Call Done Ethernet Documents Last Call Done
Fragmentation LC Done TDM Requirements LC Done SONET Documents Last Call
Done TDM Documents Last Call Done Frame Relay Documents Last Call Done
FCS retention Last Call Done MPLS PW Control Word LC Apr 2006 PPP/HDLC
PW LC Apr 2006 PWE3 MIBs Last Call Apr 2006 VCCV Last Call Apr 2006
MS-PW Architecture LC Apr 2006 PW Protection and Restoration
Requirements LC May 2006 Wildcard FEC LC Jun 2006 MS-PW Requirements LC
Jun 2006 PW OAM LC Aug 2006 PW Protection and Restoration Architecture
LC Aug 2006 Fiber Channel LC Aug 2006 MS-PW LC Jan 2007 PW Security
Considerations LC Jun 2007 PW Protection and Restoration LC Jun 2007
IP/MPLS PW LC Jun 2007 TDM Signaling LC

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