Technical Summary
The service described in this document, the Virtual Private
LAN Service (VPLS), also known as Transparent LAN Service,
offers a variant of a Layer 2 Virtual Private Network (L2VPN).
In the case of VPLS, a multipoint network connects the VPN
customers, in contrast to the more traditional Layer 2 VPNs,
which are point-to-point in nature. This document describes the
functions required to offer VPLS, mechanisms for signaling a
VPLS, and rules for forwarding and learning from VPLS frames
across a packet switched network, how to separate traffic in different
VPN and to de-multiplex traffic at the PE routers. The VPLS-LDP is
agnostic when it comes to discovery of VPLS end-points.
Working Group Summary
The VPLS solutions have been one of the controversies of the
VPN working groups. There have been two sets of solutions and
much arguing on the relative merits of these solutions. An agreement
was reached that it is not really the choice of signaling protocol
that is the major difference between the LDP and BGP based
solutions, but the kind of environment they are targeted for.
VPLS-LDP targets networks (e.g., metro) where BGP is typically
not run or LDP is used for other L2VPNs (e.g., VPWS). On the other
hand, VPLS-BGP targets those networks where L3VPNs using BGP
are also deployed. The VPLS-BGP has been through a number of
reviews, including reviews in the l2vpn working group and the idr
group. The same type of review has been done for vpls-ldp from the
l2vpn and mpls working groups.
Protocol Quality
The protocol is implemented and deployed. A fair number of
vendors have implemented the spec. The number of deployments is
large. We have not had any reviewer standing up and saying that
there is any need for major rework.
Note to RFC Editor
Please add a normative reference to RFC 2119 and cite it in section 1.
Please retitle this document as:
Virtual Private LAN Service (VPLS) using LDP Signaling
IESG Note
The L2VPN Working Group produced two separate documents,
[RFC-draft-ietf-l2vpn-vpls-ldp] and [RFC-draft-ietf-l2vpn-vpls-bgp], that
ultimately perform similar functions in different manners. Be aware that each
method is commonly referred to as "VPLS" even though they are distinct and
incompatible with one another.