Pseudowire Emulation Edge to Edge (pwe3) ---------------------------------------- Charter Last Modified: 2008-09-11 Current Status: Active Working Group Chair(s): Stewart Bryant Matthew Bocci Internet Area Director(s): Jari Arkko Mark Townsley Internet Area Advisor: Mark Townsley Technical Advisor(s): David Black Secretary(ies): David Sinicrope 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 protocols. 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 service. 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 considerations. 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 VCCV LC Done PWE3 Services MIBs LC Done PPP/HDLC PW 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 Internet-Drafts: Posted Revised I-D Title ------ ------- -------------------------------------------- Jun 2002 Jan 2008 Pseudowire (PW) Management Information Base (MIB) Jun 2002 Jan 2008 Pseudowire (PW) over MPLS PSN Management Information Base (MIB) Jun 2002 Feb 2009 Definitions of Textual Conventions for Pseudowires (PW) Management Aug 2002 Jan 2008 SONET/SDH Circuit Emulation Service Over Packet (CEP) Management Information Base (MIB) Using SMIv2 Oct 2002 Feb 2009 Ethernet Pseudowire (PW) Management Information Base (MIB) Oct 2003 Oct 2008 Managed Objects for ATM over Packet Switched Network (PSN) May 2004 Oct 2008 Managed Objects for TDM over Packet Switched Network (PSN) Sep 2004 Nov 2008 Pseudo Wire (PW) OAM Message Mapping Jul 2005 Feb 2009 Segmented Pseudowire Jan 2006 Feb 2009 An Architecture for Multi-Segment Pseudowire Emulation Edge-to-Edge Mar 2006 Jan 2009 Encapsulation Methods for Transport of Fibre Channel frames Over MPLS Networks May 2007 Feb 2009 Application of Ethernet Pseudowires to MPLS Transport Networks Nov 2007 Feb 2009 Bidirectional Forwarding Detection (BFD) for the Pseudowire Virtual Circuit Connectivity Verification (VCCV) Feb 2008 Sep 2008 Preferential Forwarding Status bit definition Mar 2008 Sep 2008 Pseudowire (PW) Redundancy Sep 2008 Sep 2008 Requirements for Point-to-Multipoint Pseudowire Dec 2008 Feb 2009 LDP extensions for AII reachability Jan 2009 Jan 2009 Reliable Fibre Channel Transport Over MPLS Networks Request For Comments: RFC Stat Published Title ------- -- ----------- ------------------------------------ RFC3916 I Oct 2004 Requirements for Pseudo-Wire Emulation Edge-to-Edge (PWE3) RFC3985 I Mar 2005 PWE3 Architecture RFC4197 I Nov 2005 Requirements for Edge-to-Edge Emulation of Time Division Multiplexed (TDM) Circuits over Packet Switching Networks RFC4385 PS Feb 2006 Pseudowire Emulation Edge-to-Edge (PWE3) Control Word for Use over an MPLS PSN RFC4448 PS Apr 2006 Encapsulation Methods for Transport of Ethernet Over MPLS Networks RFC4447 PS Apr 2006 Pseudowire Setup and Maintenance using the Label Distribution Protocol (LDP) RFC4446BCP Apr 2006 IANA Allocations for Pseudowire Edge to Edge Emulation (PWE3) RFC4553 PS Jun 2006 Structure-Agnostic Time Division Multiplexing (TDM) over Packet (SAToP) RFC4623 PS Aug 2006 Pseudowire Emulation Edge-to-Edge (PWE3) Fragmentation and Reassembly RFC4619 PS Sep 2006 Encapsulation Methods for Transport of Frame Relay Over MPLS Networks RFC4618 PS Sep 2006 Encapsulation Methods for Transport of PPP/High-Level Data Link Control (HDLC) over MPLS Networks RFC4720 PS Nov 2006 Pseudowire Emulation Edge-to-Edge (PWE3) Frame Check Sequence Retention RFC4717 PS Dec 2006 Encapsulation Methods for Transport of Asynchronous Transfer Mode (ATM) over MPLS Networks RFC4816 PS Feb 2007 Pseudowire Emulation Edge-to-Edge (PWE3) Asynchronous Transfer Mode (ATM) Transparent Cell Transport Service RFC4842 PS Apr 2007 Synchronous Optical Network/Synchronous Digital Hierarchy SONET/SDH) Circuit Emulation over Packet (CEP)) RFC4863 PS May 2007 Wildcard Pseudowire Type RFC5003 PS Sep 2007 Attachment Individual Identifier (AII) Types for Aggregation RFC5086 I Dec 2007 Structure-Aware Time Division Multiplexed (TDM) Circuit Emulation Service over Packet Switched Network (CESoPSN) RFC5087 I Dec 2007 Time Division Multiplexing over IP (TDMoIP) RFC5085 PS Dec 2007 Pseudowire Virtual Circuit Connectivity Verification (VCCV) A Control Channel for Pseudowires RFC5287 PS Aug 2008 Control Protocol Extensions for the Setup of Time-Division Multiplexing (TDM) Pseudowires in MPLS Networks RFC5254 I Oct 2008 Requirements for Multi-Segment Pseudowire Emulation Edge-to-Edge (PWE3)