> On 19 Feb 2014, at 20:17, Marc Binderberger <[email protected]> wrote: > > Hello Damien, > > thanks for the reply! > >> If you have a solution to continuously synchronise ITRs caches, we >> would be very happy to look at them and integrate them in the proposed >> solution. > > And I was curious to see a light-weight protocol extension from you :-) > Seriously, was wondering if you see an elegant, light way to implement > this in the LISP protocol (?).
Well directly using LISP maybe we could imagine something with map-notify and multicast to keep caches synchronized but I have to think more about that. Damien Saucez > >> the purpose of the document is to deal with planned restart of routers >> meaning that we know exactly when the routeur will get down then up >> (it is controlled by the operator). > > but then the "Traffic deflection to other ITRs (or a PxTR)" could be > used to fill the cache of the 2nd ITR (the one that is not reloaded). > You turn it on on ITR2 (off on ITR1), change your IGP to send all LISP > data to remote sites to ITR2, "wait a bit", then ITR2 should be ready, > you turn off deflection on ITR2 and reload ITR1. Then turning on > deflection on ITR1 and bring the IGP routing back to active-active (or > whatever the setup was before). > > > Regards, Marc > > > > > > >> On Wed, 19 Feb 2014 09:38:54 +0100, Damien Saucez wrote: >> Hello Marc, >> >>> On 18 Feb 2014, at 23:48, Marc Binderberger <[email protected]> wrote: >>> >>> Hello Damien/Olivier/Luigi/Clarence & LISP experts, >>> >>> had a look at draft-saucez-lisp-itr-graceful-03. And wonder if there is >>> more to come? >> >> Thank you for the interest. We are indeed thinking on ways to extend >> the document and provide more details on the ways the solutions could >> be implemented. >> >> >>> Somehow section 4 feels a bit "short". >>> >>> What I mean: if you try to solve the problem of the _two_ cache-miss >>> storms - first on the 2nd ITR (ITR2) when your restarting ITR (ITR1) >>> goes down, then on the restarting ITR1 when it picks up traffic again - >>> then section 4 would probably need to talk about a permanent cache >>> synchronization (?). Unless you want to solve a planned restart only. >>> But for a failure of the ITR1 I don't see how the solution you describe >>> would work >>> >>> o ITR cache synchronization: upon startup, the ITR synchronizes its >>> cache with the other ITRs in its synchronization set. The ITR is >>> marked as available only after the cache is synchronized. >>> >>> as ITR2 would trigger the cache-miss storm for the traffic after ITR1 >>> failure. >>> >>> Or if you want to solve only the cache-miss storm when ITR1 comes back >>> into the traffic stream then the ITR deflection has the advantage to >>> not require any cache-synchronization protocol, IMHO. The rate of >>> Map-Requests could be throttled to turn the storm into a breeze. The >>> method how to transport traffic to ITR2 could be one of many - a direct >>> LAN, GRE, Lisp. >>> >>> >>> So my question in short: are you planning to add some words about a >>> permanent cache synchronization? >> >> For now we don't have acceptable techniques to keep caches >> synchronised in a permanent way but I don't think it is a big issue as >> the purpose of the document is to deal with planned restart of routers >> meaning that we know exactly when the routeur will get down then up >> (it is controlled by the operator). >> >> If you have a solution to continuously synchronise ITRs caches, we >> would be very happy to look at them and integrate them in the proposed >> solution. >> >> Thank you, >> >> Damien Saucez >> >>> >>> Thanks & Regards, >>> Marc >> _______________________________________________ lisp mailing list [email protected] https://www.ietf.org/mailman/listinfo/lisp
