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). It will also address requirements driven by cloud computing services and data centers as they apply to Layer-2 VPN services.
Layer-2 VPNs defined by L2VPN operate over pseudowires (PWs) as defined by the PWE3 WG or over IP or MPLS PSN tunnels. A L2VPN emulates a "native" service over a PSN that is adequately faithful to, but may not be entirely indistinguishable from the native service itself. Further, following in the "edge-to-edge" nature of the service, the L2VPN WG will not define any 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 the PEs which provide the L2VPN connectivity.
Layer-2 VPNs comprise the following:
1. Virtual Private LAN Service (VPLS) -- A Layer-2 service that emulates a switched Ethernet (V)LAN across a 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 a PSN.
3. Virtual Private Multicast Service (VPMS) -- A Layer-2 service that provides point-to-multipoint connectivity for a variety of link layers across a PSN.
4. IP-only L2VPN, an IP-only service over a PSN. The WG will address two specific types of IP-only L2VPN:
a) Point-to-point Layer-2 VPN. This service is similar to VPWS, but also supports heterogenous Attachment Circuits at either end of a single point-to-point service.
b) Multipoint-to-multipoint Layer-2 VPN. This service is similar to VPLS, but learns IP and MAC address bindings from ARPs and broadcast/multicast IP packets.
5. Ethernet VPN (E-VPN) - An enhanced Layer-2 service that emulates an Ethernet (V)LAN across a PSN. E-VPN supports load-sharing across multiple connections from a Layer-2 site to an L2VPN service. E-VPN is primarily targeted to support large-scale L2VPNs with resiliency requirements not satisfied by other L2VPN solutions.
6. E-Tree, a Layer-2 service defined by the MEF, which provides connectivity between one or more root nodes and one or more leaf nodes, with the restriction that leaf nodes may only communicate with root node(s) (and not with each other).
L2VPNs 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 PEs participating in a Layer-2 VPN as well as the membership of CE devices for a specific instance of an L2VPN.
The L2VPN WG will provide extensions of existing protocols that will be discussed in protocol-specific WGs. In particular, the L2VPN WG may define extensions to pseudowire management mechanisms for VPLS. Those extensions will be reviewed by the PWE3 WG to ensure they are aligned with the overall design/architecture of PWE3.
The L2VPN WG will not define new encapsulations, control, or resiliency mechanisms specifically related to pseudowires. Furthermore, when the L2VPN solution is based on PWs, the L2VPN WG will not define protocol inter-working between an L2VPN and native service Layer-2 OAM or resiliency mechanisms. The L2VPN WG may define how to operate native service-layer control, OAM or resiliency mechanisms on top of an L2VPN. In addition, it may define native data plane and/or control plane interworking between an L2VPN and an associated native Layer-2 service.
The L2VPN WG scope includes the following:
1. Discovery of PEs participating in a Layer-2 VPN and the associated topology required for connectivity of the VPLS, VPWS, VPMS or E-VPN service.
2. Signaling of information related to the discovery and membership of PEs 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, when the L2VPN operates over PWs. Once those requirements have been reviewed by the L2VPN WG, they should be provided to the PWE3 WG to derive solutions.
3. MIBs for Layer-2 VPN solutions.
4. Specification of requirements, framework and solutions that facilitate Operations Administration and Management (OAM) of any type of L2VPN within the scope of the L2VPN Working Group.
5. Mechanisms to permit optimization of multicast data traffic within an L2VPN.
6. If transport does not involve PWs, mechanisms that support load-balancing/multi-pathing between PEs interconnecting a Layer-2 service using an L2VPN across the PSN.
7. requirements for the multi-homing of CEs to several VPLS or E-VPN PEs, inclusive of active/backup and active/ active (load-sharing) configurations. Based on these requirements define VPLS or E-VPN control plane solutions for achieving fast convergence after failure of an active path in the PSN or on the AC side.
8. Enhancements to increase the scalability of the Control Plane and Data Plane of L2VPN PE nodes, and of core nodes that provide transport services for L2VPN.
9. Requirements and solutions for Auto-Discovery and Signaling of Inter-AS L2VPNs, in addition to Inter-AS solutions for multicast-optimized L2VPNs.
10. Requirements and solutions for supporting "E-Tree" services using VPLS.
Submit an I-D describing MIB for VPLS
Submit an I-D describing MIB for VPWS
Submit an I-D on OAM requirements for VPLS
Submit an I-D on OAM requirements for VPWS
Submit L2 requirements to IESG for publication as Informational RFC
Submit L2 framework to IESG for publication as Informational RFC
Identify VPLS and VPWS solutions for the WG
Submit VPLS solution documents to IESG
Submit VPWS solution documents to IESG
Submit Auto-Discovery and Signaling for Intra-AS and Inter-AS VPLS and VPWS Layer-2 VPNs
Submit IP-only L2VPN solution documents to IESG
Submit OAM solutions for VPWS to IESG
Submit OAM solutions for VPLS to IESG
Submit signaling solution for multicast-optimized VPLS to IESG
Submit I-D on Virtual Private Multicast Service (VPMS) requirements to IESG
Submit MIB for VPLS to IESG
Submit MIB for VPWS to IESG
Submit scalability solutions for VPLS Data-Plane to IESG
Submit scalability solutions for VPLS Control-Plane to IESG
Submit E-Tree requirements/framework to IESG
Submit MIB for IP-only L2VPN to IESG
Submit OAM solutions for IP-only L2VPN to IESG
Submit Auto-Discovery solution for VPMS to IESG
Submit VPLS service convergence improvement solutions to IESG