Hi,
If I understand correctly the problem PCE (i+1) has complete knowledge the inter AS link (i+1) -> i but not the i->(i+1) link properties (upstream). First I would tend to understand the following section of RFC5441 as : PCE (i) can verify the link properties in the i->(i+1) direction This should solve the problem mentioned except in the case the algorithm require to know the link properties in both direction at the same time, but the draft does not address this problem either. Please indicate if I missed something. “ Step i: For i=n-1 to 2: PCE(i) computes VSPT(i), the tree made of the shortest constrained paths between each BN-en(j,i) and the TE LSP destination. It does this by considering its own TED and the information in VSPT(i+1). In the case of inter-AS TE LSP computation, this also requires adding the inter-AS TE links that connect the domain(i) to the domain(i+1). “ From: [email protected] [mailto:[email protected]] On Behalf Of ext JP Vasseur Sent: Wednesday, July 27, 2011 12:05 AM To: Fatai Zhang Cc: [email protected]; [email protected]; 王磊 Subject: Re: [Pce] request timeslot for draft-wang-pce-inter-as-extentions-01 That was my question too On Jul 26, 2011, at 1:55 PM, Fatai Zhang wrote: Hi all, RFC5392 is a kind of mechamism and it is already there. Why we need to define another solution based on some nonexistent assumption? Fatai Thanks ----- Original Message ----- From: JP Vasseur <mailto:[email protected]> To: [email protected] Cc: [email protected] ; [email protected] ; ͵ <mailto:[email protected]> Sent: Tuesday, July 26, 2011 1:20 AM Subject: Re: [Pce] request timeslot for draft-wang-pce-inter-as-extentions-01 Hi, On Jul 25, 2011, at 11:16 AM, [email protected] wrote: Hi JP, IMO, we don't need two methods. The method of extending IGP may impact on large aspect. Extending BRPC and PCEP defined in this draft is enough. So let the WG decide which one of the methods is most appropriate Thanks. JP. Thanks, Xihua JP Vasseur <[email protected]> ȋ: [email protected] 2011-07-25 ςΧ 08:30 ʕȋ ͵ <[email protected]> ˍ [email protected] ַ̢ Re: [Pce] request timeslot for draft-wang-pce-inter-as-extentions-01 Thanks for your feed-back. It would be interesting to hear from the WG if indeed we need two methods. To each specific problem we can certainly find a number of way to solve it, but let's try to make sure that we do not specify a new technique if we can use what exist today. WG ? Thanks. JP. On Jul 25, 2011, at 12:25 AM, ͵ wrote: Hi, Xuerong and PCEers I have read the draft. It provides an alternate method that extends BRPC and PCEP protocol to get TE information of Inter-AS biderectional links. In my opinion, It is useful for the smooth upgrade of existing MPLS/GMPLS networks to support Inter-AS bidirectional path computation, because it need not any extension or modification to the IGP (such as OSPF and IS-IS) used in MPLS/GMPLS-enabled routers/switches. However, the method of IGP extension is also applicable and suitable for new network-equipments. So, I think there is no conflict between these two metods. The draft could be used in the scenario where the IGP extension of Inter-AS biderectional links can not be supported. Thanks. Lei Wang Tsinghua University, Beijing, China [email protected] <mailto:[email protected]> or [email protected] <mailto:[email protected]> _______________________________________________ Pce mailing list [email protected] <mailto:[email protected]> https://www.ietf.org/mailman/listinfo/pce <https://www.ietf.org/mailman/listinfo/pce> _______________________________________________ Pce mailing list [email protected] https://www.ietf.org/mailman/listinfo/pce ________________________________ _______________________________________________ Pce mailing list [email protected] https://www.ietf.org/mailman/listinfo/pce
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