Configuring BGP and OSPF to BGP always prefer.

[Jaime Soto Valenzuela]

Hi,

I´m configuring a VPNv4 between two sites. In principal site I receive some prefixes through OSPF and in the backup site the same prefixes through OSPF. I´m redistributing OSPF routes through BGP to backup site.

In summary, in backup site the ASR9K receives the same prefixes through OSPF (local) and BGP but ASR must prefer BGP routes

instead of OSPF.

How can I configure it?.

Thanks.

[Ivan Krimmel]

Hi Jaime,

a L3 network topology would possibly help to understand your goals and challenges. In general, in scenarios with OSPF and VPNv4 there's a challenge, that OSPF prefixes will be preferred indeed, if the two sites have a backdoor link. To overcome this, there's a feature in OSPF called 'sham-link', which makes the prefixes learned across the backbone(and hence via MP-BGP) more prefrred.

HTH,

Ivan.