Constructing protection paths for inter-AS, inter-sub-AS P2MP TE-LSPs
draft-mjsraman-pce-inter-as-p2mp-protect-03

PCE Working Group                                          Shankar Raman
Internet draft                                             Balaji Venkat
Intended Status: Experimental RFC                           Gaurav Raina
Expires: July 2013                                         I.I.T, Madras
                                                        January 25, 2013

 Constructing protection paths for inter-AS, inter-sub-AS P2MP TE-LSPs
              draft-mjsraman-pce-inter-as-p2mp-protect-03

Abstract

   Constructing primary and backup explicit path Point-to-Multipoint
   Label Switched Paths is important from the point of view of providing
   protection switching in case the primary fails.

   It is absolutely essential that the backup P2MP LSPs constructed do
   not share risk with any of the links and nodes of the primary path.
   In the case of inter-AS P2MP TE-LSPs or in the case of inter-sub-AS
   (in the case of BGP-Confederations being deployed) P2MP TE-LSPs where
   BGP confederations are deployed within an AS, such protection
   switching can be provided by calculating primary and backup multicast
   distribution trees (read P2MP TE-LSPs) that dont intersect with each
   other.

   In this paper we propose a method by which inter-sub-AS P2MP TE-LSPs
   (hence even inter-AS P2MP TE-LSPs) can be constructed by first
   finding the AS level topology of the network (be it inter-AS or
   inter-sub-AS within a single AS) in question and secondly to compute
   the paths in such a way that they dont intersect or if necessary in
   the worst case partially intersect each other. The proposed scheme is
   explained with an example and subsequent discussion is done to
   elucidate its benefits to multicast in particular. 

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Table of Contents

   1  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1  Terminology . . . . . . . . . . . . . . . . . . . . . . . .  3
   2  Methodology of the proposal . . . . . . . . . . . . . . . . . .  3
   3  Discussion  . . . . . . . . . . . . . . . . . . . . . . . . . .  8
     3.1 Discussion of Algorithms to be used  . . . . . . . . . . . .  9
   4  Security Considerations . . . . . . . . . . . . . . . . . . . . 11
   5  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 11
   6  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     6.1  Normative References  . . . . . . . . . . . . . . . . . . . 11
     6.2  Informative References  . . . . . . . . . . . . . . . . . . 12
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13

 

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1  Introduction

   In the context of P2MP TE-LSPs being constructed for carriage of
   multicast traffic across multiple areas within a given AS employing
   BGP confederations  where such an autonomous system  may comprise of
   more than one BGP confederation instance, and if such multicast
   traffic is mission critical traffic then it would be most useful to
   have backup protection trees (where such trees represent entire P2MP