The Layer 2 Tunneling Protocol, Version 3, (L2TPv3) defines a
protocol for tunneling a variety of payload types over IP networks.
This document defines how to carry an MPLS label stack and its
payload over L2TPv3. This enables an application which traditionally
requires an MPLS-enabled core network to utilize an L2TPv3
encapsulation over an IP network instead.
Working Group Summary
There is a need for one or more approaches to run MPLS over a
datagram (IP) infrastructure. Options include MPLS directly over
IP, MPLS over GRE, or MPLS over L2TP. There is some difference of
opinion regarding which approach to use, but there is rough
consensus to go ahead with this approach, and some who see
advantages (particularly wrt security) for this approach. Also,
given that this is currently deployed, there is a significant
value in documenting this approach.
Ross Callon has reviewed the spec for the IESG. There are multiple
implementations, although as far as I know they are from one
(very large) vendor. The protocol has been deployed in more than
There are a few minor editorial nits that were pointed out in
Gen-ART review. The authors intend to update the draft to fix
these minor nits, but intend to do this at the same time as
any IESG comments are addressed.