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Using Multipoint LDP When the Backbone Has No Route to the Root
RFC 6512

Approval announcement
Draft of message to be sent after approval:


From: The IESG <>
To: IETF-Announce <>
Cc: RFC Editor <>,
    mpls mailing list <>,
    mpls chair <>
Subject: Protocol Action: 'Using Multipoint LDP when the Backbone has no Route to the Root' to Proposed Standard (draft-ietf-mpls-mldp-recurs-fec-04.txt)

The IESG has approved the following document:
- 'Using Multipoint LDP when the Backbone has no Route to the Root'
  (draft-ietf-mpls-mldp-recurs-fec-04.txt) as a Proposed Standard

This document is the product of the Multiprotocol Label Switching Working

The IESG contact persons are Adrian Farrel and Stewart Bryant.

A URL of this Internet Draft is:

Ballot Text

Technical Summary

  LDP is one of the core MPLS protocols. It was orginally designed
  to establish point-to-point and multipoint-to-point LSPs that 
  reflected the topology as understood by the IGP routing protocol.
  LDP has since been extended for several different uses.

  When LDP is used as the control protocol for constructing 
  Point-to-Multipoint and Multipoint-to-Multipoint Label Switched 
  Paths ("MP LSPs") it contains a field that identifies the address 
  of a "root node". Intermediate nodes are expected to be able to 
  look up that address in their routing tables. However, if the route
  to the root node is a BGP route, and if the intermediate nodes
  are part of a BGP-free core, this lookup will fail.  

  This document specifies procedures which enable a MP LSP to be 
  constructed through a BGP-free core. In these procedures, the root 
  node address is temporarily replaced by an address that is known 
  to the intermediate nodes and is on the path to the true root node.

Working Group Summary

  The document has been well reviewed by the MPLS working group.
  There were no issues arrising. 

Document Quality

   There is one known implementation of this specification, and
   a number of other vendors have indicated their intention to


  Loa Andersson ( is the Document Shepherd.
  Adrian Farrel ( is the Responsible AD.

RFC Editor Note