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Address Resolution Protocol (ARP) Mediation for IP Interworking of Layer 2 VPNs
RFC 6575

Approval announcement
Draft of message to be sent after approval:


From: The IESG <>
To: IETF-Announce <>
Cc: RFC Editor <>,
    l2vpn mailing list <>,
    l2vpn chair <>
Subject: Protocol Action: 'ARP Mediation for IP Interworking of Layer 2 VPN' to Proposed Standard (draft-ietf-l2vpn-arp-mediation-19.txt)

The IESG has approved the following document:
- 'ARP Mediation for IP Interworking of Layer 2 VPN'
  (draft-ietf-l2vpn-arp-mediation-19.txt) as a Proposed Standard

This document is the product of the Layer 2 Virtual Private Networks
Working Group.

The IESG contact persons are Stewart Bryant and Adrian Farrel.

A URL of this Internet Draft is:

Ballot Text

Technical Summary

A Virtual Private Wire Service (VPWS) provides a point-to-point 
connection service between a pair of Customer Edge (CE) devices 
over an IP/MPLS packet switched network using Pseudowire
Emulation Edge to Edge (PWE3) technology.  It does so by 
binding two Attachment Circuits (ACs), each connecting a CE 
device with a Provider Edge (PE) device, to a Pseudowire (PW) 
extended between the two PEs. PWE3 defines PW types 
that interconnect ACs of the same technology (homogeneous ACs), 
e.g., both ACs being Ethernet. In general, a VPWS provides
connectivity between homogeneous ACs using the existing 
PWE3 technology. However, if the ACs are layer2 attachment 
circuits of heterogeneous types (e.g., one AC is Ethernet and 
the other one is a Fame Relay DLCI), and solely carry IP
datagrams in the corresponding packet data units' payload, 
it is possible to provide a VPWS that interconnects these 
ACs using IP Layer2 Transport PWs often referred to simply 
as IP PWs. This requires the PEs to perform a function known
as "ARP Mediation".  ARP Mediation refers to the process of 
resolving IP addresses to Layer 2 addresses when different 
address resolution protocols are used on either Attachment 
Circuit.  The methods described in this document are applicable 
even when the CEs run a routing protocol between them 
as long as the routing protocol runs over IP.

Working Group Summary

This document has been in existence since the very beginning 
of the PPVPN and L2VPN WG's.  At first, it only included 
support for IPv4, but subsequently was updated to include 
support for IPv6. Ultimately, this document provides a means
of interworking IPv4-enabled ACs, IPv6-enabled ACs and 
dual-stack IPv4/IPv6-enabled ACs whereby the ACs are of 
disparate Layer2 technologies. 

Document Quality
There are no concerns about document quality. 
Several implementations of  this draft have existed in
the field for several years.

Nabil Bitar ( is the Document Shepherd.
Stewart Bryant ( is the Responsible 
Area Director.

RFC Editor Note

In section 2

A PE that is to perform ARP Mediation for IPv6 packets SHOULD
perform the following logical steps:
A PE that is to perform ARP Mediation for IPv6 packets MUST
perform the following logical steps:
In section 4.3.3 - two places 
- end of list item 2
- end of first sentence list item 3
In section 4.3.4 second para

link-layer address of the local AC
link layer address of the PE interface attached to local AC

RFC Editor Note