Hi Stewart, It sounds good to me, except for the proposed tie breaker mechanism. As you know, today there is no existing mechanism for LDP to advertise the TLDP listening IP address in the IGP. So in short/mid term rLFA deployment, no IGP solution would be available. So the draft must propose a last resort "working" tie breaker. IMHO, using the lowest numerical value would be a very bad idea ... because this has no sense (just tie break, but without any insurance that the chosen prefix would be good)
In order to bring more insurance, at least, I think the the tie breaker must check that the prefix used is an internal one (when possible ...) and is a /32. I don't think we could make something more precise because otherwise we would need to address IGP protocol specifities (TLVs, LSAs ... fields to check...). Thoughts ? -----Message d'origine----- De : Stewart Bryant [mailto:[email protected]] Envoyé : lundi 28 octobre 2013 19:25 À : LITKOWSKI Stephane DTF/DERX; Hannes Gredler Cc : [email protected]; rogeriomariano; [email protected] Objet : Re: I-D Action: draft-ietf-rtgwg-remote-lfa-02.txt How about the following text: To establish an targeted LDP session with a candidate PQ node the repairing node (S) needs to know what IP address PQ is willing to use for targeted LDP sessions. Ideally this is provided by PQ advertising this address in the IGP in use. Which address is used, how this is advertised in the IGP, and whether this is a special IP address or an IP address also used for some other purpose is out of scope for this document and must be specified in an IGP specific RFC. In the absence of a protocol to learn the prefered IP address for targetted LDP, a tie-breaking mechanism is required. Unless otherwise configured, an LSR should attempt a targeted LDP session with the IP address with the lowest numerical value advertised by the target LSR. To determine the lowest numerical value the address is taken in network byte order and cast to an integer of appropriate size. (in case you are wondering about the appropriate size, it to have common v4 and v6 text) - Stewart _________________________________________________________________________________________________________________________ Ce message et ses pieces jointes peuvent contenir des informations confidentielles ou privilegiees et ne doivent donc pas etre diffuses, exploites ou copies sans autorisation. Si vous avez recu ce message par erreur, veuillez le signaler a l'expediteur et le detruire ainsi que les pieces jointes. Les messages electroniques etant susceptibles d'alteration, Orange decline toute responsabilite si ce message a ete altere, deforme ou falsifie. Merci. This message and its attachments may contain confidential or privileged information that may be protected by law; they should not be distributed, used or copied without authorisation. If you have received this email in error, please notify the sender and delete this message and its attachments. As emails may be altered, Orange is not liable for messages that have been modified, changed or falsified. Thank you. _______________________________________________ rtgwg mailing list [email protected] https://www.ietf.org/mailman/listinfo/rtgwg
