I don't want, because I can't accomodate, failover of A to B and B to A. What I do have the bandwidth between networks to do is fail over a subset (VIP customers) of A to B and vice versa. My guess is to advertise a /21 via each and a /24 from each /21 on both for the fail over to be for those /24s specifically.
-Ty On Mar 19, 2014 8:01 PM, "Mike Hammett" <[email protected]> wrote: > I'm not sure what your plan is with that /24. If you advertise that /20 > out both providers, the entire Internet can reach that /20 from either > provider. If either provider fails, your entire address space is available > on the other. No need to do anything except contact your failed upstream to > get the connection repaired. If you want to weight traffic based on > (relative) geography, advertise the /20 out both providers in addition to > one /21 out provider A and one /21 out provider B. Traffic will prefer the > /19 until that provider fails. > > > > ----- > Mike Hammett > Intelligent Computing Solutions > http://www.ics-il.com > > ----- Original Message ----- > > From: "Ty Featherling" <[email protected]> > To: "Mikrotik discussions" <[email protected]> > Sent: Wednesday, March 19, 2014 7:51:18 PM > Subject: Re: [Mikrotik] BGP guidance > > We have a /20 assignment that I will be using on both sides. I intend to > have a /24 on each side that will fail over. > > -Ty > On Mar 19, 2014 5:19 PM, "Mike Hammett" <[email protected]> wrote: > > > Just as an example, if you have a /23 from both providers, announce that > > /23 on both connections. Then, advertise the two /24s comprising the /23 > on > > the ISP you want to use it from. I believe BGP will take a longer prefix > > before a prepend. The smallest you can advertise, though, is a /24, so if > > your blocks are smaller, that won't work. > > > > > > > > > > ----- > > Mike Hammett > > Intelligent Computing Solutions > > http://www.ics-il.com > > > > ----- Original Message ----- > > > > From: "Ty Featherling" <[email protected]> > > To: "Mikrotik discussions" <[email protected]> > > Sent: Wednesday, March 19, 2014 2:11:43 PM > > Subject: [Mikrotik] BGP guidance > > > > I am ready to begin turning up BGP on both of my edge routers and start > > advertising my new IPv4 assignment. I am want to make sure I understand > > things clearly first. > > > > These were setup as two separate networks, each with their own upstream. > We > > built out between them and got a backhaul between the two so we could > > manage the far network from the one we have our office already on. I > turned > > up OSPF recently on all routers and the routes for both networks are > shared > > between the two edge routers. > > > > Now we have our own IP space and would like to start advertising/using > it. > > That seems easy enough. Turn BGP on between the edge routers and our > > upstream providers and advertise some addresses on one and some on the > > other. The real fun begins when we want to have fail-over between the > two. > > Initially this will only be for some VIP clients like ISDs and Hospitals. > > In the event of an outage upstream of either network I would like to make > > sure these clients stay up across the backhaul between networks. > > > > I believe the way to accomplish this is just to announce the space used > by > > those clients to both upstream ASes and just prepend the ones that > normally > > live on the other network. That way should the upstream go down, the > > "farther" path will become active. Beyond that I just need to have iBGP > > running between my two edge routers so those routes are known. Does this > > sound right? > > -------------- next part -------------- > > An HTML attachment was scrubbed... > > URL: < > > > http://mail.butchevans.com/pipermail/mikrotik/attachments/20140319/5b3303be/attachment.html > > > > > _______________________________________________ > > Mikrotik mailing list > > [email protected] > > http://mail.butchevans.com/mailman/listinfo/mikrotik > > > > Visit http://blog.butchevans.com/ for tutorials related to Mikrotik > > RouterOS > > > > -------------- next part -------------- > > An HTML attachment was scrubbed... > > URL: < > > > http://mail.butchevans.com/pipermail/mikrotik/attachments/20140319/da153495/attachment.html > > > > > _______________________________________________ > > Mikrotik mailing list > > [email protected] > > http://mail.butchevans.com/mailman/listinfo/mikrotik > > > > Visit http://blog.butchevans.com/ for tutorials related to Mikrotik > > RouterOS > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://mail.butchevans.com/pipermail/mikrotik/attachments/20140319/9631979e/attachment.html > > > _______________________________________________ > Mikrotik mailing list > [email protected] > http://mail.butchevans.com/mailman/listinfo/mikrotik > > Visit http://blog.butchevans.com/ for tutorials related to Mikrotik > RouterOS > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://mail.butchevans.com/pipermail/mikrotik/attachments/20140319/338fe859/attachment.html > > > _______________________________________________ > Mikrotik mailing list > [email protected] > http://mail.butchevans.com/mailman/listinfo/mikrotik > > Visit http://blog.butchevans.com/ for tutorials related to Mikrotik > RouterOS > -------------- next part -------------- An HTML attachment was scrubbed... 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