[c-nsp] eBGP peering traversing non-BGP routers

[Robert Blayzor]

Consider the following network:

http://tinyurl.com/2nrv3z


All routers except C1, C2, and D1 run BGP.

An eBGP multi-hop session was established between D2 and B1.  The
sessions come up, routes exchange fine.  B1 learns of the peers address
via the OSPF area it's in (redistributed static route from C2) and D1
and D2 have static routing to get to the loopback address on B1.
Everything appears to work ok except...

B1 sees the network and the next hop as D2 via static route, sends it to
C1.  The problem appears that routes advertised from D2 to B1 cannot
make it back to D1 or D2 because the non-BGP speaking routers don't know
about the routes.  ie: if you trace from B1, it goes to C1 and then C1
will just route the network to it's default route.

I assume the only way to get this to work is some type of BGP to OSPF
redistribution?  Other suggestions were to just GRE tunnel from D2 to B1
(ugly).  Or perhaps just make C1 and C2 part of the iBGP network and be
done with it.

Just looking for suggestions or ideas.

-- 
Robert Blayzor, BOFH
INOC, LLC
rblayzor\@(inoc.net|gmail.com)
PGP: 0x66F90BFC @ http://pgp.mit.edu
Key fingerprint = 6296 F715 038B 44C1 2720  292A 8580 500E 66F9 0BFC

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