Pseudowire Emulation Edge to Edge (pwe3) ---------------------------------------- Charter Last Modified: 2006-10-03 Current Status: Active Working Group Chair(s): Stewart Bryant Danny McPherson Internet Area Director(s): Jari Arkko Mark Townsley Internet Area Advisor: Mark Townsley Secretary(ies): Matthew Bocci 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: Posted Revised I-D Title ------ ------- -------------------------------------------- Jun 2002 Jun 2006 Pseudo Wire (PW) Management Information Base Jun 2002 Jun 2006 Pseudo Wire (PW) over MPLS PSN Management Information Base Jul 2002 Jun 2006 SONET/SDH Circuit Emulation over Packet (CEP) Aug 2002 Jun 2006 SONET/SDH Circuit Emulation Service Over Packet (CEP) Management Information Base Using SMIv2 Oct 2002 Jun 2006 Ethernet Pseudo Wire (PW) Management Information Base Oct 2002 Mar 2006 Encapsulation Methods for Transport of Frame Relay Over MPLS Networks Oct 2002 May 2006 Encapsulation Methods for Transport of ATM Over MPLS Networks Jun 2003 May 2006 Encapsulation Methods for Transport of PPP/HDLC Over MPLS Networks Jul 2003 Jun 2006 Pseudo Wire Virtual Circuit Connectivity Verification (VCCV) Nov 2003 Sep 2005 PWE3 Frame Check Sequence Retention Feb 2004 May 2006 Structure-aware TDM Circuit Emulation Service over Packet Switched Network (CESoPSN) Feb 2004 Jun 2006 TDM over IP Aug 2004 Apr 2006 PWE3 ATM Transparent Cell Transport Service Jun 2005 May 2006 Requirements for inter domain Pseudo-Wires Jan 2006 Jun 2006 Dynamic Placement of Multi Segment Pseudo Wires Jan 2006 May 2006 An Architecture for Multi-Segment Pseudo Wire Emulation Edge-to-Edge Mar 2006 Jun 2006 Encapsulation Methods for Transport of Fibre Channel frames 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 RFC4446BCP Apr 2006 IANA Allocations for Pseudowire Edge to Edge Emulation (PWE3) RFC4447 PS Apr 2006 Pseudowire Setup and Maintenance using the Label Distribution Protocol (LDP) RFC4448 PS Apr 2006 Encapsulation Methods for Transport of Ethernet Over MPLS Networks 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