Robert, >From: Robert Raszuk [mailto:[email protected]] >Sent: Thursday, May 10, 2012 >3:23 PM > >Bruno, > > > 2. On the iBGP side, (re-) advertises the path received over > > the eBGP session being shutdown with a low LOCAL_PREF. > >Sounds good.
Great. >Btw what is "low" ? Low enough such as a backup path will be preferred. We can add this in the draft. > Is 0 low ? Is 5 low ? Should we at least recommend >some value if you are assuming automation in g-shut to local pref >translation ? Local pref value are choosen independantly by each AS. There is no way we can pick a value -except 0 may be- which will work all the time. Even 0 may not be perfect: - 0 could already be used by others path we should never be choosen even during a ghsut. - In an Internet network, to optimize the convergence steps and the transient behavior we should/may pick the lower value assigned to the kind of relationship being gshut (e.g. peer). Indeed, if we gshut an eBGP session with a peering policy, BGP may transiently pick any path including a path from a transit provider. This would lead to a transient withdraw to peers due to policy restriction (transit path are not advertised to peer). This is suboptimal. OTOH an ISP may not want to spend time/money to optimize this... In short: local_pref value are a local policy. We can clearly discuss this in the draft, but OTOH a least one person had commented that the draft was too long and could fit in 1-2 pages. Bruno >Jakob, Jeff, > > > This is for ebgp only, not ibgp. right? > >I was assuming this is mostly for ibgp. > >If this is also for ebgp are you suggesting that we will receive from >the peer a single error in UPDATE message for SAFI X/X and then it will >trigger full re-advertisement of all of our routes for all of our SAFIs >over such session to this peer with g-shut ? > > >The way I read what Jeff proposed is this: > >1. We are receiving N errors and just treat-as-withdraw or drop errored >optional attributes when applicable > >2. When N becomes more then X send g-shut to eBGP peer and lower local >pref towards iBGP then re-advertise > >3. After time T shut EBGP session. > >Questions: What is value of X and T above ? > >Thx, >R. > > > > > _________________________________________________________________________________________________________________________ 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, France Telecom - 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, France Telecom - Orange is not liable for messages that have been modified, changed or falsified. Thank you. _______________________________________________ GROW mailing list [email protected] https://www.ietf.org/mailman/listinfo/grow
