On Oct 5, 2013, at 11:43 AM, Christopher Morrow <morrowc.li...@gmail.com> wrote:
> On Sat, Oct 5, 2013 at 2:08 PM, joel jaeggli <joe...@bogus.com> wrote: >> >> On Oct 5, 2013, at 9:45 AM, Christopher Morrow <morrowc.li...@gmail.com> >> wrote: >> >>> you really don't want to do policy routing :( >>> >> >> PBR has this tendency to be brittle in the face of topology changes. > > yup, exactly my point :( > >> There are much better way to outbound load-balance between providers >> offering same or similar quality routes to the same destination. >> >> multi-AS multipath will do that if the peers are on the same router. >> BGPaddpath >> can do it for you if the peers are spread across routers. > > these both will require seeing the longer prefix from the right peer > though, right? and selecting that would just be like natural selection > anyway… so at this level if I can install two best paths in the fib then great I'll just hash flows between them… this does nothing for source based path selection but it does a lot for load-balancing between peers especially if there's substantial overlap of equidistant paths. If you have say 2914/3356 and you look at the amount of traffic that you can load-balance between them instead of simply tie-breaking on router-id or however far do your path algorythm you get, it's significant enough to matter. > yikes, I suppose you could: > 1) generate the longer prefix internally > 2) set it's next-hop to something reachable out both (all) peers > 3) metric the preferred peer's next-hop appropriately > 4) profit > > but that sounds also kind of messy and prone to odd failures when > changes are made :( I go for the low hanging fruit, which is better usage of the information I already have. > you'd be adding complexity that you'd have to track through the life > of your network :( (and explain to anyone 'not you' working on the > network) > > -chris > >> joel >> >>> On Sat, Oct 5, 2013 at 12:19 PM, Anurag Bhatia <m...@anuragbhatia.com> >>> wrote: >>>> Hello there! >>>> >>>> >>>> I am trying to do a source based outbound routing between multiple >>>> upstreams. Usually I picked outbound via localpref but here I wish to use >>>> Provider 1 for say 10.10.10.0/24 while provider 2 for small chunk of it say >>>> 10.10.10.0/28. I wish to keep failover support and thus so if provider 2 >>>> fails, I wish to push traffic again via Provider 1. >>>> >>>> Is this is possible only with VRF or I can push for some specific match >>>> rule in route maps? >>>> >>>> >>>> >>>> Thanks. >>>> >>>> -- >>>> >>>> >>>> >>>> Anurag Bhatia >>>> anuragbhatia.com >>>> >>>> Linkedin <http://in.linkedin.com/in/anuragbhatia21> | >>>> Twitter<https://twitter.com/anurag_bhatia> >>>> Skype: anuragbhatia.com >>> >> >
signature.asc
Description: Message signed with OpenPGP using GPGMail
