multihome bgp with ospf

12.01.10   |  
‎12-01-2010 09:11 PM


we have 2 border routers that run ospf towards the internal network, CE1 & 2. The border routers also have a single EBGP link each to a PE router, PE1 & 2, so the network is multi-homed to a single provider. Both PEs are within the same AS. I've set the BGP pref/med with policy so that there is deterministic routing through CE1-PE1 as preferred and a default route is passed from the SP.
For IGP integration I was initially going to export a conditional BGP default into OSPF at each CE based on whether it was passed via local EBGP peer and was going to set the OSPF metric for external route preferencing within OSPF so that the default route via CE1 would be preferred. This resulted in non-deterministic installation of the conditional default at one or other of the CEs.
What's the best way to route traffic through CE1-PE1 under normal conditions and sync OSPF routing with BGP so the inbound and outbound routing is synced across IGP/BGP.



Re: multihome bgp with ospf

12.02.10   |  
‎12-02-2010 11:33 AM

Have you tried injecting a 0/0 OSPF LSA Type 5 E1 routes from your CE1/CE2 with CE2 being slightly higher in OSPF link cost?

Doug Hanks

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