We mean that those inter-ASBR TE LSPs which are permitted by policy/scaling configuration to be propagated outside can be flooded by BGP.
This may be a sub-set of TE LSPs specifically provisioned for carrying inter-AS TE traffic and may be a full mesh. If all the ASes support such a mechanism then the itner-AS TE path can be calculated using the inter-AS graph of such LSPs and inter-AS links. But, this may not be always possible though because of policy and scaling constraints.In such situations we can only find the possible AS paths after eliminating the paths through inter-AS links which are not feasible and then use methods like BRPC to complete the path setup. Regards Vijay -----Original Message----- From: JP Vasseur [mailto:[EMAIL PROTECTED] Sent: Saturday, February 03, 2007 4:05 AM To: Vijayanand C - TLS, Chennai. Cc: [EMAIL PROTECTED] Subject: Re: [Pce] RE: I-D ACTION:draft-vijay-somen-pce-bgp-interas-te-path-01.txt Hi, Let me first try to make sure of something here. When you write "The PCE shall learn the TE attributes of the inter-AS TE links and the TE tunnels that exist between the ASBRs in the domain." Are you suggesting to flood via BGP the intra-domain TE LSPs ? In other words, suppose the following scenario: AS1---AS2---AS3 You have a mesh of intra-domain TE LSPs between all ASBRs within AS2. Are you suggesting to flood in AS1 these TE LSPs (and this for all other ASes that might be between AS1 and the destination domain) ? Thanks. JP. On Feb 1, 2007, at 12:48 AM, Vijayanand C - TLS, Chennai. wrote: Are you suggesting that BGP should propagate all possible next-hops/As paths and regular path selection process avoided for all prefixes which can be destinations of inter-AS TE tunnels ? The inter-AS TE link information can be made aware only to the ASes on either side of the inter-AS link by the IGP. It may not be possible to propagate it beyond that ( or can it ?). So some of the possible AS paths found by BGP( if we propagate all next-hops/aspaths in bgp) may not be worth trying for path setup (by BRPC) because of violation of some TE constraint. In our proposal we can pick the paths which are really feasible, since we have the inter-AS graph, and then invoke methods like BRPC Regards Vijay -----Original Message----- From: JP Vasseur [mailto:[EMAIL PROTECTED] Sent: Thursday, February 01, 2007 1:19 AM To: Vijayanand C - TLS, Chennai. Cc: [EMAIL PROTECTED] Subject: Re: [Pce] RE: I-D ACTION:draft-vijay-somen-pce-bgp-interas-te-path-01.txt Hi, On Jan 25, 2007, at 9:32 AM, Vijayanand C - TLS, Chennai. wrote: Hello all, We have submitted the following I-D, please send in your comments/suggestions * speaking as a technical contributor * In [BRPC], a method to optimally compute a inter-domain TE path for MPLS and GMPS LSPs using the PCE architecture detailed in [PCE_ARCH] is described. However the method described requires the list of Autonomous systems or domains to be determined apriori. Determining the list of ASes/domains to be traversed to reach a destination, satisfying the TE constraints is non-trivial. It requires knowledge of the inter-AS connectivity and the TE characteristics of the inter-AS links along with the knowledge of the available paths within each of the ASes/domains. BGP contains information on the list of ASes to be traversed to reach a destination, however BGP route selection and decision process truncates most of the feasible paths, and it also does not carry the TE characteristics of the inter-AS links and path availability within a domain. What does prevent you from relying on BGP to provide you all possible paths toward a specific destination skipping the regular path selection process for specific routes (see proposals made in the past) and then use BRPC as currently specified? The Inter-AS TE link could easily be obtained via the IGP with minor additions. This is in my opinion a fundamental question that must first be addressed before moving forward. Thanks. JP. Regards Vijay -----Original Message----- From: [EMAIL PROTECTED] [ <mailto:[EMAIL PROTECTED]> mailto:[EMAIL PROTECTED] Sent: Tuesday, January 23, 2007 2:20 AM To: <mailto:[email protected]> [email protected] Subject: I-D ACTION:draft-vijay-somen-pce-bgp-interas-te-path-01.txt A New Internet-Draft is available from the on-line Internet-Drafts directories. Title : A BGP based method to compute inter-AS Traffic engineering Label Switched Paths with PCE Author(s) : C. Vijayanand, S. Bhattacharya Filename : draft-vijay-somen-pce-bgp-interas-te-path-01.txt Pages : 26 Date : 2007-1-22 The ability to compute an optimal path for setting up Traffic engineering Label Switched Paths spanning multiple autonomous systems managed by different operators has been a key requirement in MPLS and GMPLS networks. This document specifies a method of computing inter-AS paths consisting of a list of ASes to be traversed and a list of TE-Tunnels to be traversed in each AS. The method described here uses BGP speakers in the PCEs of each AS to distribute the inter-AS connectivity information and the TE-Tunnels in each AS to its neighbors to facilitate the construction of an inter-AS topology graph which can be used for computing inter-AS paths. A URL for this Internet-Draft is: <http://www.ietf.org/internet-drafts/draft-vijay-somen-pce-bgp-interas-t e> http://www.ietf.org/internet-drafts/draft-vijay-somen-pce-bgp-interas-te -path-01.txt DISCLAIMER: ------------------------------------------------------------------------ ----------------------------------------------- The contents of this e-mail and any attachment(s) are confidential and intended for the named recipient(s) only. It shall not attach any liability on the originator or HCL or its affiliates. Any views or opinions presented in this email are solely those of the author and may not necessarily reflect the opinions of HCL or its affiliates. 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