[nsp] ospf default routes and bgp injection

Christopher J. Wolff chris at bblabs.com
Wed Mar 31 11:58:12 EST 2004


> You are better off running iBGP on all the routers, instead of
> redistributing BGP into OSPF. Your IGP is supposed to be kept small and
> clean, and is supposed to carry only the infrastructure prefixes.
> 
> Redistributing BGP to your IGP is a general no-no :)

Oops :)  It was late.

> > With option 2, If router B advertises its default route, it becomes
> default
> > gateway for all current and new ospf area 0 members, which is not
> desirable.
> 
> Assuming that that is the only egress path, it should not be an issue.

Yes, but it seems to create a loop on Router B that runs the CPU up.

> 
> Assuming that you run iBGP between Router A and Router D, it should not
> matter, since even if both Router B and E defaults to Router A and D
> respectively, the more specific routes learnt via eBGP (propagated via
> iBGP)
> will ensure that the shortest path to the destination is used.
> 
> regards,
> Lim Fung
> --
> 

I've considered ibgp as an end-to-end solution however never went so far as
to implement it.  My concern is making sure that the entire routing table
isn't propagated all the way to the edge device, which could be something
minimal like a 2611XM.  Any thoughts?  Thank you for your advice.

Christopher



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