Pseudo Wire Emulation Edge to Edge (pwe3)

Last Modified: 2006-01-12

Chair(s):

  • mailto:stbryant@cisco.com

  • mailto:danny@arbor.net

    Internet Area Director(s):

  • mailto:townsley@cisco.com

  • mailto:margaret@thingmagic.com

    Internet Area Advisor:

  • mailto:townsley@cisco.com

    Secretary(ies):

  • mailto:matthew.bocci@alcatel.co.uk

    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.

    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 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 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 protocols.

    WG Objectives:

    Specify the following PW types:

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

    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    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
    Apr 2006    Multi-Segment PW Requirements LC
    Apr 2006    VCCV LC
    Apr 2006    PWE3 Services MIBs LC
    Apr 2006    PPP/HDLC PW LC
    May 2006    Wildcard FEC LC
    May 2006    PW Protection and Restoration Requirements LC
    Jun 2006    PW OAM Mapping LC
    Jun 2006    Multi-Segment PW Architecture LC
    Jul 2006    TDM Signaling LC
    Aug 2006    PW Protection and Restoration Architecture
    Aug 2006    Fiber Channel LC
    Dec 2006    Multi-Segment PW LC
    Mar 2007    PW Protection and Restoration LC

    Internet-Drafts:

    Pseudo Wire (PW) Management Information Base (122245 bytes)
    Pseudo Wire (PW) over MPLS PSN Management Information Base (60461 bytes)
    Definitions for Textual Conventions and OBJECT-IDENTITIES for Pseudo-Wires Management (21457 bytes)
    SONET/SDH Circuit Emulation over Packet (CEP) (96033 bytes)
    Encapsulation Methods for Transport of Ethernet Over MPLS Networks (46797 bytes)
    Pseudowire Setup and Maintenance using the Label Distribution Protocol (76368 bytes)
    Ethernet Pseudo Wire (PW) Management Information Base (55048 bytes)
    PWE3 Fragmentation and Reassembly (36647 bytes)
    Encapsulation Methods for Transport of Frame Relay Over MPLS Networks (35606 bytes)
    Encapsulation Methods for Transport of ATM Over MPLS Networks (79753 bytes)
    IANA Allocations for pseudo Wire Edge to Edge Emulation (PWE3) (20437 bytes)
    Encapsulation Methods for Transport of PPP/HDLC Over MPLS Networks (33323 bytes)
    Pseudo Wire Virtual Circuit Connectivity Verification (VCCV) (41981 bytes)
    Structure-Agnostic TDM over Packet (SAToP) (46853 bytes)
    PWE3 Frame Check Sequence Retention (19739 bytes)
    Structure-aware TDM Circuit Emulation Service over Packet Switched Network (CESoPSN) (76490 bytes)
    TDM over IP (102345 bytes)
    Managed Objects for TDM over Packet Switched Network (PSN) (80314 bytes)
    PWE3 ATM Transparent Cell Transport Service (10069 bytes)
    Pseudo Wire (PW) OAM Message Mapping (79849 bytes)
    PWE3 Control Word for use over an MPLS PSN (23704 bytes)
    Requirements for inter domain Pseudo-Wires (50680 bytes)
    Segmented Pseudo Wire (58100 bytes)
    Dynamic Placement of Multi Segment Pseudo Wires (39155 bytes)
    An Architecture for Multi-Segment Pseudo Wire Emulation Edge-to-Edge (42271 bytes)
    Target Choice of Pseudowire Type (10078 bytes)

    Request For Comments:

    Requirements for Pseudo-Wire Emulation Edge-to-Edge (PWE3) (RFC 3916) (43856 bytes)
    PWE3 Architecture (RFC 3985) (95062 bytes)
    Requirements for Edge-to-Edge Emulation of Time Division Multiplexed (TDM) Circuits over Packet Switching Networks (RFC 4197) (47937 bytes)
    IETF Secretariat - Please send questions, comments, and/or suggestions to ietf-web@ietf.org.

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