Subject: Re: [mpls] I-D Action:draft-ietf-mpls-ldp-p2mp-09.txt

From: "Dutta, Pranjal K (Pranjal)" <[email-masked]>
Date: Mon, 10 May 2010 07:51:56 +0530

Authors and the WG,

     I have one question on the following section of the I-D.

Section 2.4.1.1 Determining one's 'upstream LSR'

   When there are several candidate upstream LSRs, the LSR MAY select

   one upstream LSR using the following procedure:

   1.  The candidate upstream LSRs are numbered from lower to higher IP

       address

   2.  The following hash is performed: H = (Sum Opaque value) modulo N,

       where N is the number of candidate upstream LSRs

   3.  The selected upstream LSR U is the LSR that has the number H.

   This allows for load balancing of a set of LSPs among a set of

   candidate upstream LSRs, while ensuring that on a LAN interface a

   single upstream LSR is selected.

Can somebody explain this math of "Sum Opaque value"? Doesn't look

like with this math we can arrive at H.

Thanks,

Pranjal

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Subject: [mpls] I-D Action:draft-ietf-mpls-ldp-p2mp-09.txt

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, et al.

      Filename        : draft-ietf-mpls-ldp-p2mp-09.txt

      Pages           : 37

      Date            : 2010-04-30

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.  These extensions are also referred

to as mLDP Multicast LDP. mLDP constructs the P2MP or MP2MP LSPs

without interacting with or relying upon any other multicast tree

construction protocol.  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.

A URL for this Internet-Draft is:

http://www.ietf.org/internet-drafts/draft-ietf-mpls-ldp-p2mp-09.txt

Internet-Drafts are also available by anonymous FTP at:

ftp://ftp.ietf.org/internet-drafts/

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Internet-Draft.