Layer 2 Virtual Private Networks (l2vpn) ---------------------------------------- Charter Last Modified: 2010-11-29 Current Status: Active Working Group Chair(s): Giles Heron Nabil Bitar Routing Area Director(s): Stewart Bryant Adrian Farrel Routing Area Advisor: Stewart Bryant Technical Advisor(s): Alex Zinin Mailing Lists: General Discussion:l2vpn@ietf.org To Subscribe: https://www.ietf.org/mailman/listinfo/l2vpn Archive: http://www.ietf.org/mail-archive/web/l2vpn/current/maillist.html Description of Working Group: The L2VPN working group is responsible for defining and specifying a limited number of solutions for supporting provider-provisioned Layer-2 Virtual Private Networks (L2VPNs). Layer-2 VPN's comprise the following: 1. Virtual Private LAN Service (VPLS) -- A Layer-2 service that emulates an Ethernet (V)LAN across an IP or an MPLS-enabled IP Packet Switched Network (PSN). 2. Virtual Private Wire Service (VPWS) -- A Layer 2 service that provides point-to-point connectivity for a variety of link layers, including Frame Relay, ATM, Ethernet, PPP, etc., across an IP or MPLS-enabled IP PSN. 3. Virtual Private Multicast Service (VPMS) -- A Layer 2 service that Provides point-to-multipoint connectivity for a variety of link layers, including Frame Relay, ATM, Ethernet, PPP, etc., across an IP or MPLS-enabled IP PSN. 4. IP-only L2VPN -- A point-to-point or point-to-multipoint "IP-only" service over an IP or MPLS-enabled PSN. This service is similar to VPWS because it supports a variety of link-layer protocols on the Attachment Circuits, including Frame Relay, ATM, Ethernet, PPP, etc. IP-only L2VPN's are different from both VPLS and VPWS because unicast Layer-2 frames containing IP data packets, either IPv4 or IPv6, are de- encapsulated leaving only the IP data packet to be transmitted over the PSN. An IP-only L2VPN service also differs from L3VPN service, since no routing protocol operates between the PE and CE; furthermore, connectivity from CE to CE is provided via an emulated Layer-2 service over the PSN, which results in the CE's appearing to be directly attached to each other at Layer-2. The WG will address two specific types of IP-only L2VPN: a) Those with Attachment Circuits (ACs) that use the same Layer 2 framing at all attachment points in the same L2VPN; and, b) Those with ACs that use different Layer 2 framing at various attachment points in the same L2VPN. For (b), inter-working between link-layers is strictly out of scope beyond that which is minimally necessary to ensure that IP packets are transported from an AC of one type, across the IP or MPLS-enabled IP PSN, and to an AC of another type in as transparent a manner as possible to the CEs on both sides of the service. VPLS, VPWS and VPMS operate over Pseudowires (PWs) as defined by the PWE3 WG. As with a single PW, an L2VPN emulates a "native" service over a PSN that is reasonably faithful to, but may not be entirely indistinguishable from, the native service itself. Further, following in the "edge-to-edge" nature of the PWs that it uses, the L2VPN WG will not define any new mechanisms which exert control over the underlying PSN. When necessary it may, however, recommend or require the use of existing PSN QoS and path control mechanisms between PW endpoints which make up the L2VPN. L2VPN's will make use of existing IETF specified mechanisms unless there are technical reasons why the existing mechanisms are insufficient or unnecessary. The L2VPN WG is responsible for specification of the discovery and membership of PE's participating in a VPLS, VPWS or IP-only L2VPN as well as the membership of CE devices to a specific instance of a L2VPN. The L2VPN WG will provide extensions of existing protocols that will be discussed in protocol-specific WG's. In particular, the L2VPN WG may define extensions to pseudowire management mechanisms (including OAM), specifically Pseudowire Virtual Circuit Connectivity Verification (VCCV), for VPLS. Those VCCV extensions will be reviewed by PWE3 to ensure they are inline with the overall design/architecture of VCCV and MPLS. The L2VPN WG will not define new encapsulations, control (set-up, configuration, maintenance or tear-down), or resiliency mechanisms specifically related to pseudowires, because those must be defined by the PWE3 WG. Furthermore, the L2VPN WG will not define protocol inter- working between a VPLS or VPWS and native service-layer control, OAM or or resiliency mechanisms, as those will be defined by the PWE3 WG. On the other hand, the L2VPN WG may define how to operate native service- layer control, IEEE 802.1 OAM or resiliency mechanisms on top of a VPLS or VPWS service. The L2VPN WG scope includes the following: 1. Discovery of PE's participating in a Layer-2 VPN and the associated topology required for connectivity of the VPLS or VPWS service. 2. Signaling of information related to the discovery and membership of PE's within a L2VPN. These procedures must use PWE3 control and management procedures, or define requirements for extensions of PWE3 protocols to suit the needs of an L2VPN. Once those requirements are reviewed by the L2VPN WG, they should be provided to the PWE3 WG to derive solutions. 3. MIB's for Layer-2 VPN solutions. 4. Specification of requirements and framework that will define Operations Administration and Management (OAM) procedures for VPLS and VPWS VPN's, related to the operation of VPLS and VPWS VPN's over IP/MPLS PSN's. In addition, the L2VPN WG will define OAM solutions for VPLS and VPWS VPN's. 5. Mechanisms to permit optimization of multicast data traffic within a VPLS or VPWS VPN over an IP/MPLS PSN. 6. Improved service convergence for multi-homed CE's to VPLS PE's. Specifically, upon failure of a primary path from a CE to VPLS PE, initiate a rapid switch-over to an alternate path. If required, interactions with native service-layer resiliency mechanisms will be provided via solutions from other IETF WG's such as PWE3. 7. Enhancements to increase the scalability of the Control Plane and Data Plane (e.g.: number of PW's and MAC Forwarding Database, respectively) of VPLS PE nodes. 8. Define requirements and solutions for Auto-Discovery and Signaling of Inter-AS VPLS and VPWS L2VPN's, in addition to Inter-AS solutions for multicast-optimized VPLS and VPMS Layer-2 VPN's. The L2VPN WG currently works on the following tasks: - Define MIB's appropriate for each type of Layer-2 VPN. - Specification of Operations Administration and Management (OAM) mechanisms for VPLS, VPWS and IP-only VPN's. - Specification of procedures to permit optimization of L2VPN multicast data traffic within the PSN. - Define enhancements to increase scalability of VPLS PE nodes, to provide aggregation of learned customer MAC addresses at VPLS PE's. - Identify requirements for multi-homing of CE's to VPLS PE's. elements. Based on these requirements, define solutions for achieving fast convergence after a switchover to an alternate path, for example through optimized MAC flushing within a VPLS domain. - Identify requirements for Inter-AS VPLS and VPWS services. Define Inter-AS enhancements to VPLS and VPWS based on these requirements. - Include extensions to L2VPN protocols and RFC's necessary to create an MPLS Transport Profile (MPLS-TP). The work on the MPLS TP needs to be coordinated between four primary working groups (MPLS, PWE3, L2VPN and CCAMP) that are chartered to do MPLS TP work. Where necessary, the WG will coordinate its activities with IEEE 802.1 and ITU. Goals and Milestones: Done Submit an I-D describing MIB for VPLS Done Submit an I-D describing MIB for VPWS Done Submit an I-D on OAM requirements for VPLS Done Submit an I-D on OAM requirements for VPWS Done Identify VPLS and VPWS solutions for the WG Done Submit L2 framework to IESG for publication as Informational RFC Done Submit L2 requirements to IESG for publication as Informational RFC Done Submit VPLS solution documents to IESG Done Submit VPWS solution documents to IESG Done Submit Auto-Discovery and Signaling for Intra-AS and Inter-AS VPLS and VPWS Layer-2 VPN's Nov 2008 Submit IP-only L2VPN solution documents to IESG Mar 2009 Submit OAM solutions for VPWS to IESG Mar 2009 Submit OAM solutions for VPLS to IESG Mar 2009 Submit signaling solution for multicast-optimized VPLS to IESG Mar 2009 Submit I-D on Virtual Private Multicast Service (VPMS) requirements to IESG Mar 2009 Submit PIM snooping solution for VPLS to IESG Mar 2009 Submit OAM solutions for IP-only L2VPN to IESG Jul 2009 Submit MIB for VPLS to IESG Jul 2009 Submit MIB for VPWS to IESG Jul 2009 Submit MIB for IP-only L2VPN to IESG Nov 2009 Submit scalability solutions for VPLS Data-Plane to IESG Nov 2009 Submit scalability solutions for VPLS Control-Plane to IESG Nov 2009 Submit Auto-Discovery solution for VPMS to IESG Jul 2010 Submit VPLS service convergence improvement solutions to IESG Jul 2010 Submit VPLS multi-homing solutions to IESG Internet-Drafts: Posted Revised I-D Title ------ ------- -------------------------------------------- Oct 2004 Mar 2011 ARP Mediation for IP Interworking of Layer 2 VPN Oct 2005 Mar 2011 OAM Procedures for VPWS Interworking Jul 2006 Oct 2010 VPLS Interoperability with CE Bridges Aug 2007 Mar 2011 Virtual Private Lan Services (VPLS) Management Information Base May 2009 Mar 2011 Extensions to VPLS PE model for Provider Backbone Bridging Jan 2010 Mar 2011 VPLS Interoperability with Provider Backbone Bridges Feb 2011 Jun 2011 Extension to LDP-VPLS for Ethernet Broadcast and Multicast Request For Comments: RFC Stat Published Title ------- -- ----------- ------------------------------------ RFC4665 I Sep 2006 Service Requirements for Layer 2 Provider Provisioned Virtual Private Networks RFC4664 I Sep 2006 Framework for Layer 2 Virtual Private Networks (L2VPNs) RFC4762 PS Jan 2007 Virtual Private LAN Service (VPLS) Using Label Distribution Protocol (LDP) Signaling RFC4761 PS Jan 2007 Virtual Private LAN Service (VPLS) Using BGP for Auto-discovery and Signaling RFC5501 I Mar 2009 Requirements for Multicast Support in Virtual Private LAN Services RFC6074 PS Jan 2011 Provisioning, Autodiscovery, and Signaling in L2VPNs RFC6136 I Mar 2011 Layer 2 Virtual Private Network (L2VPN) Operations, Administration, and Maintenance (OAM) Requirements and Framework