Coordinated Multicast Trees (CMT) for Transparent Interconnection of Lots of Links (TRILL)

Approval announcement
Draft of message to be sent after approval:

From: The IESG <>
To: "IETF-Announce" <>
Cc:,,,,, "The IESG" <>,
Subject: Protocol Action: 'Coordinated Multicast Trees (CMT) for TRILL' to Proposed Standard (draft-ietf-trill-cmt-11.txt)

The IESG has approved the following document:
- 'Coordinated Multicast Trees (CMT) for TRILL'
  (draft-ietf-trill-cmt-11.txt) as Proposed Standard

This document is the product of the Transparent Interconnection of Lots
of Links Working Group.

The IESG contact persons are Alvaro Retana, Alia Atlas and Deborah

A URL of this Internet Draft is:

Technical Summary

The TRILL base protocol facilitates loop free connectivity to
non-TRILL networks via choice of an Appointed Forwarder for a set of
VLANs.  Appointed Forwarders provides load sharing based on VLAN with
an active-standby model. High performance operations require an
active-active load sharing model with rapid fail over and load
spreading on a per flow basis.  Active-Active load sharing can be
accomplished by representing any given non-TRILL network with a single
virtual RBridge. Virtual representation of the non-TRILL network with
a single RBridge poses serious challenges in multi-destination RPF
(Reverse Path Forwarding) check calculations.  This document specifies
required enhancements to build Coordinated Multicast Trees (CMT)
within the TRILL campus to solve RPF related issues.

Working Group Summary

This draft was developed by the WG over a two year period.  There has
been relatively little controversy over the technical content of the
draft. It has good WG support.

Document Quality

This document is of good quality. CMT is implemented in the Cisco
Nexus product line.


     Document Shepherd:  Donald Eastlake, 3rd
     Responsible Area Director:  Alia Atlas