2.6.13 Pseudowire Emulation Edge to Edge (pwe3)

NOTE: This charter is a snapshot of the 77th IETF Meeting in Anaheim, California USA. It may now be out-of-date.

Last Modified: 2010-03-25


Andrew Malis <andrew.g.malis@verizon.com>
Matthew Bocci <matthew.bocci@alcatel-lucent.com>

Routing Area Director(s):

Stewart Bryant <stbryant@cisco.com>
Adrian Farrel <adrian.farrel@huawei.com>

Routing Area Advisor:

Stewart Bryant <stbryant@cisco.com>

Technical Advisor(s):

David Black <black_david@emc.com>


David Sinicrope <david.sinicrope@ericsson.com>

Mailing Lists:

General Discussion: pwe3@ietf.org
To Subscribe: pwe3-request@ietf.org
In Body: subscribe your_email_address
Archive: http://www.ietf.org/mail-archive/web/pwe3/index.html

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.
Some service providers wish to use MPLS technology to
replace existing transport network infrastructure, relying
upon pseudowire technology is an integral component of
these network convergence architectures.

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 or point-to-multipoint
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 unnecessary.

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 endpoints of the PW.

PWE3 will co-ordinate this with the AVT and TICTOC WGs.
Where AVT or TICTOC require extensions to PWs to support
time or frequency transfer this work will be undertaken by
the PWE3 WG in co-ordination with the these WGs.

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.
PWE3 will work with the MPLS, L2VPN and other relevant WGs
for definitions of common solutions for the secure operation
of pseudowires.

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.  Congestion
avoidance may be more difficult with P2MP pseudowires than
P2P pseudowires. The WG will consider both cases.

PWE3 will work closely with the L2VPN WG to ensure a clear
demarcation is defined for where PWE3 stops and L2VPN starts,
in particular in defining point-multipoint (P2MP) PWs.

PWE3 will work with MPLS and L2VPN to enhance the OAM suite
for transport applications. 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

The IETF PWE3 WG is the design authority for pseudo-wire
over IP/MPLS PSN technology. An entity or individual that
wishes to propose extensions or changes to this technology
must bring the corresponding proposals to the PWE3 WG that
would treat them via a process similar to one described in
RFC 4929 for the MPLS/GMPLS change process.

WG Objectives:

Specify the following PW types:

Most of the initial specific PW types have been specified
(e.g., Frame Realy, Ethernet, ATM). Investigation into
and specification of a "generic PW" type and/or MPLS PW
should be undertaken.

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
unless the Network Layer protocol is IP or MPLS.

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

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.

Publish document outlining PW-specific congestion avoidance
and response guidelines.

Publish document outlining PW-specific security

Specify requirements and mechanisms for P2MP functionality
for PWs. This work will be coordinated with the L2VPN and
MPLS working groups.

Publish requirements and specification for PW to take
advantage of multiple PSN paths that exist between PEs.

Publish requirements and specification for enhanced OAM.

Include extensions to the PWE3 protocols and RFCs
necessary to create an MPLS Transport Profile (MPLS-TP).
The work on the MPLS TP needs to be coordinated between
three primary working groups (MPLS, PWE3, L2VPN and CCAMP) that
are chartered to do MPLS TP work.

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  PW 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  Multi-Segment PW Requirements LC
Done  PWE3 Services MIBs LC
Done  Wildcard FEC LC
Done  TDM Signaling LC
Jul 2008  Multi-Segment Architecture LC
Done  Basic Pseudowire MIBs LC
Sep 2008  Fiber Channel Encap LC
Sep 2008  PW OAM Mapping LC
Sep 2008  Congestion Framework LC
Oct 2008  Multi-Segment PW LC
Dec 2008  PW Protection and Restoration Requirements LC
Dec 2008  PW Congestion Response LC
Dec 2008  Generic PW Requirements
Jan 2009  Dynamic MS PW LC
Mar 2009  PW Protection and Restoration Architecture
Mar 2009  Multipath PW LC
Mar 2009  Generic Associated Channel Header LC
Apr 2009  MPLS PW LC
Jul 2009  PW Protection and Restoration LC
Jul 2009  Multisegment PW MIB
Jul 2009  Congestion Solution LC
Jul 2009  Security Considerations LC
Jul 2009  P2MP Requirements LC
Dec 2009  Enhanced PW OAM
Dec 2009  VCCV Extensions for MPLS-TP
Dec 2009  Tandem Connection Monitoring for PWs


  • draft-ietf-pwe3-cep-mib-13.txt
  • draft-ietf-pwe3-oam-msg-map-12.txt
  • draft-ietf-pwe3-segmented-pw-15.txt
  • draft-ietf-pwe3-fc-encap-10.txt
  • draft-ietf-pwe3-mpls-transport-04.txt
  • draft-ietf-pwe3-redundancy-bit-03.txt
  • draft-ietf-pwe3-redundancy-03.txt
  • draft-ietf-pwe3-p2mp-pw-requirements-02.txt
  • draft-ietf-pwe3-ldp-aii-reachability-04.txt
  • draft-ietf-pwe3-mpls-eth-oam-iwk-02.txt
  • draft-ietf-pwe3-fat-pw-03.txt
  • draft-ietf-pwe3-static-pw-status-00.txt

    Request For Comments:

    RFC3916 I Requirements for Pseudo-Wire Emulation Edge-to-Edge (PWE3)
    RFC3985 I PWE3 Architecture
    RFC4197 I Requirements for Edge-to-Edge Emulation of Time Division Multiplexed (TDM) Circuits over Packet Switching Networks
    RFC4385 PS Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for Use over an MPLS PSN
    RFC4446 BCP IANA Allocations for Pseudowire Edge to Edge Emulation (PWE3)
    RFC4447 PS Pseudowire Setup and Maintenance using the Label Distribution Protocol (LDP)
    RFC4448 PS Encapsulation Methods for Transport of Ethernet Over MPLS Networks
    RFC4553 PS Structure-Agnostic Time Division Multiplexing (TDM) over Packet (SAToP)
    RFC4618 PS Encapsulation Methods for Transport of PPP/High-Level Data Link Control (HDLC) over MPLS Networks
    RFC4619 PS Encapsulation Methods for Transport of Frame Relay Over MPLS Networks
    RFC4623 PS Pseudowire Emulation Edge-to-Edge (PWE3) Fragmentation and Reassembly
    RFC4717 PS Encapsulation Methods for Transport of Asynchronous Transfer Mode (ATM) over MPLS Networks
    RFC4720 PS Pseudowire Emulation Edge-to-Edge (PWE3) Frame Check Sequence Retention
    RFC4816 PS Pseudowire Emulation Edge-to-Edge (PWE3) Asynchronous Transfer Mode (ATM) Transparent Cell Transport Service
    RFC4842 PS Synchronous Optical Network/Synchronous Digital Hierarchy SONET/SDH) Circuit Emulation over Packet (CEP))
    RFC4863 PS Wildcard Pseudowire Type
    RFC5003 PS Attachment Individual Identifier (AII) Types for Aggregation
    RFC5085 PS Pseudowire Virtual Circuit Connectivity Verification (VCCV) A Control Channel for Pseudowires
    RFC5086 I Structure-Aware Time Division Multiplexed (TDM) Circuit Emulation Service over Packet Switched Network (CESoPSN)
    RFC5087 I Time Division Multiplexing over IP (TDMoIP)
    RFC5254 I Requirements for Multi-Segment Pseudowire Emulation Edge-to-Edge (PWE3)
    RFC5287 PS Control Protocol Extensions for the Setup of Time-Division Multiplexing (TDM) Pseudowires in MPLS Networks
    RFC5542 PS Definitions of Textual Conventions for Pseudowires (PW) Management
    RFC5601 PS Pseudowire (PW) Management Information Base (MIB)
    RFC5602 PS Pseudowire (PW) over MPLS PSN Management Information Base (MIB)
    RFC5603 PS Ethernet Pseudowire (PW) Management Information Base (MIB)
    RFC5604 PS Managed Objects for Time Division Multiplexing (TDM) over Packet Switched Networks
    RFC5605 PS Managed Objects for ATM over Packet Switched Networks (PSNs)
    RFC5659 I An Architecture for Multi-Segment Pseudowire Emulation Edge-to-Edge
    RFC5885 PS Bidirectional Forwarding Detection (BFD) for the Pseudowire Virtual Circuit Connectivity Verification (VCCV)

    Meeting Minutes


    Working Group Status Update - Matthew and Andy
    MPLS and Ethernet OAM Interworking - Nabil Bitar - (draft-ietf-pwe3-mpls-eth-oam-iwk-02.txt)
    Pseudowire (PW) OAM Message Mapping - Yaakov Stein - (draft-ietf-pwe3-oam-msg-map-12.txt)
    Packet Pseudowire - Stewart Bryant - (draft-bryant-pwe3-packet-pw-03.txt)
    Enhanced ECMP and Large Flow Aware Transport - Lucy Yong - (draft-yong-pwe3-enhance-ecmp-lfat-01.txt)
    Control Word Reserved bit for use in E-Tree - Simon Delord - (draft-delord-pwe3-cw-bit-etree-02.txt)
    Mandatory Features of Virtual Circuit Connectivity Verification Implementations - Nick DelRegno - (draft-delregno-pwe3-vccv-mandatory-features -00.txt)
    VPLS PE Model with E-Tree Support - Yuanlong Jiang - draft-jiang-l2vpn-vpls-pe-etree-00.txt
    Encapsulation Methods for Transport of Fibre Channel frames Over MPLS Networks - Linda Dunbar - (draft-ietf-pwe3-fc-encap-10.txt )
    MPLS-TP Pseudowire Status Maintenance Message (to be added to Pseudowire Status for Static Pseudowires) - Luca Martini - (draft-ietf-pwe3-static-pw-status-00.txt)
    LDP Extensions for MPLS-TP PW OAM configuration - Fei Zhang - (draft-zhang-mpls-tp-pw-oam-config-01.tx)
    Stewarts presentation on ACH TLV draft comments