Subject: [mpls] I-D ACTION:draft-ietf-mpls-ldp-p2mp-04.txt

From: [email-masked]
Date: Fri, 22 Feb 2008 15:30:01 -0800 (PST)

A New Internet-Draft is available from the on-line Internet-Drafts 
directories.
This draft is a work item of the Multiprotocol Label Switching Working Group of the IETF.

	Title		: Label Distribution Protocol Extensions for Point-to-Multipoint and Multipoint-to-Multipoint Label Switched Paths
	Author(s)	: I. Minei
	Filename	: draft-ietf-mpls-ldp-p2mp-04.txt
	Pages		: 34
	Date		: 2008-2-22
	
This document describes extensions to the Label Distribution Protocol
   (LDP) for the setup of point to multi-point (P2MP) and multipoint-to-
   multipoint (MP2MP) Label Switched Paths (LSPs) in Multi-Protocol
   Label Switching (MPLS) networks.  The solution relies on LDP without
   requiring a multicast routing protocol in the network.  Protocol
   elements and procedures for this solution are described for building
   such LSPs in a receiver-initiated manner.  There can be various
   applications for P2MP/MP2MP LSPs, for example IP multicast or support
   for multicast in BGP/MPLS L3VPNs.  Specification of how such
   applications can use a LDP signaled P2MP/MP2MP LSP is outside the
   scope of this document.

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---

From: Cao Wei <[email-masked]>
Date: Mon, 25 Feb 2008 11:38:18 +0800

I am happy to see this draft is updated. I believe p2mp LDP is useful 
especially for MVPN. But I have one question want to be clarified:
  Do we need to improve the error notification ability of mLDP? That is,
let LSP end (leaf nodes) know if there is a failure occurred.

  RFC 5037 documents the operational experience of LDP and Silent failures is
one of the protocol issues. Also I got some feedbacks from customer that silent
failure makes it is difficult to identify where/what the problem is, especially
the error indication is from the up layer services (such as VOIP). The
operators have to check the service related devices first since there is no 
notification from the carrier devices. This always takes time and makes the
problem more serious.

  Compared to point to point LSP, failure of p2mp LSP can cause more serious 
outage. So I wound if there should have a mechanism to propagate the failure to
the end of the LSP. I believe it is important for PE to know the LSP status and
take action immediately when there is a failure. 

Regards,
------------------				 
Cao Wei
2008-02-25