Thanks guys. I think I get it. Advertise entire block via BGP on both. Advertise /24s out as well on the preffered incoming connections but with shorter AS length. One both edge routers, share default route via OSPF. This is so that in the event that one link is down, that router will no longer share it's default route?
>From there, all downstream routers will have to have their default routes informed by OSPF. Since my network topology is basically a Y feeding a star, with the two upstream routers both connected to the same core router that then feeds the rest of the network, that core router will make all the routing decisions to send ourbound traffic to the right default route as learned from OSPF. I can manipulate that route selection by way of weigting the OSPF metrics as well as static routes with weighted differences. Does this sound like it? -Ty On Mon, Aug 31, 2015 at 2:22 PM, Scott Reed <[email protected]> wrote: > What we did was BGP advertise the whole block out out both connections and > then advertise the smaller blocks out the primary for that block. We > worked with our upstream and advertised /29 networks in some cases. Since > both BGP and OSPF use the most specific range, this works well. > So, on your 2 border routers you tell OSPF to share the default route. On > all other routers you tell OSPF not to share the default route. Based on > the costs you have setup in OSPF, some will go out one way and some the > other. You just need to make sure your costs divide the network the same > way you are doing with your BGP routes. > There are other ways to do this that I am sure other folks will share, but > this one does work. > > > On 8/31/2015 2:54 PM, Ty Featherling wrote: > >> I use OSPF to hand internal routing and BGP to talk to my provider. I just >> turned up a second circuit on the network so naturally I would like to be >> able to route some subnets through one connection and others through the >> other with either failing over should one connection go down. I get that I >> can advertise each subnet as small as /24 out of either or both >> connections >> but weighted differently so that one path is preferred while available. >> The >> question I have is how do I pass down which path should be taken on the >> outgoing side via OSPF? I'm sure it has to do with sharing default routes >> but could someone help me understand what needs done? >> >> -Ty >> -------------- next part -------------- >> An HTML attachment was scrubbed... >> URL: < >> http://mail.butchevans.com/pipermail/mikrotik/attachments/20150831/51d77b39/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 >> >> >> ----- >> No virus found in this message. >> Checked by AVG - www.avg.com >> Version: 2015.0.6086 / Virus Database: 4409/10550 - Release Date: 08/31/15 >> >> >> > -- > Scott Reed > > Wireless Networking > Network Design, Installation and Administration > Mikrotik Advanced Certified > > > > _______________________________________________ > 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/20150831/0b45a0f9/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
