Hi everyone,
here comes a bit complicated question for the routing / filter (?) experts of us:
We have two edge routers R1 and R2 (each CCR2116) which are both connected to ISPs receiving each a full table via ebgp. R2 is as well connected to an IXP. R1 and R2 are directly connected to each other and run an ibgp sessions to share their external routes.
On the inner side of our networks we use ospf as an igp. R1 and R2 are originating default routes into the ospf instance for this site.
To connect other sites (which all have their own internet uplink) we use a second ospf instance and redistribute all internal routes (no ebgp routes & no default) in between the two ospf sessions. We have other routers beside R1 and R2 on every site connecting to our external sites using ospf as well. So far this kind of meshing has been working pretty well for us.
Here comes the catch: We are planning to replace all the site-2-site ospf routing with ebgp assigning a private as to every site. We plan to redistribute the internal ospf routes into the private ebgp sessions.
Now it gets tricky: How can we make sure to only redistribute the private ebgp sessions of R1 and R2 into ospf since redistribute bgp would redistribute all the bgp routes of every instance. Route filtering (bgp-input-local-as) would definitely be an option but I worry that R1 and R2 can handle this considering their routing table is around 2-3m routes each. Has anyone any kind of experience with a setup like this or even better another idea?
We are not planning to use ibgp on the internal private as systems since ospf is doing the job. It has been working in the lab. Has anyone done this?
here comes a bit complicated question for the routing / filter (?) experts of us:
We have two edge routers R1 and R2 (each CCR2116) which are both connected to ISPs receiving each a full table via ebgp. R2 is as well connected to an IXP. R1 and R2 are directly connected to each other and run an ibgp sessions to share their external routes.
On the inner side of our networks we use ospf as an igp. R1 and R2 are originating default routes into the ospf instance for this site.
To connect other sites (which all have their own internet uplink) we use a second ospf instance and redistribute all internal routes (no ebgp routes & no default) in between the two ospf sessions. We have other routers beside R1 and R2 on every site connecting to our external sites using ospf as well. So far this kind of meshing has been working pretty well for us.
Here comes the catch: We are planning to replace all the site-2-site ospf routing with ebgp assigning a private as to every site. We plan to redistribute the internal ospf routes into the private ebgp sessions.
Now it gets tricky: How can we make sure to only redistribute the private ebgp sessions of R1 and R2 into ospf since redistribute bgp would redistribute all the bgp routes of every instance. Route filtering (bgp-input-local-as) would definitely be an option but I worry that R1 and R2 can handle this considering their routing table is around 2-3m routes each. Has anyone any kind of experience with a setup like this or even better another idea?
We are not planning to use ibgp on the internal private as systems since ospf is doing the job. It has been working in the lab. Has anyone done this?
Statistics: Posted by hannesclp — Sun Apr 06, 2025 5:04 pm