BGP local-preference and 0/0 announcment

[flokad]

Hi!

Im have the following issue (see Attach)! How to solve it? Any Idea?

Br,
Flo

[Stoffen]

Hi.

To make sure I understand your topology;
Between R1 and R2, there is no IPv4 BGP peering, only vpn-ipv4 (via VPRN)?

Can you give the output of "show router bgp routes 0.0.0.0/0"

Can you establish IPv4 peering between R1 and R2? I assume there is vpn-v4 peering running now, so in that case, its just to enable ipv4 family on iBGP.

If only connection is, and will be vpn-ipv4, then you need to import GRT routes (0.0.0.0/0) into VPRN on both R1 and R2, then export to GRT on the other side.
While doing this, make sure to set correct local-preference during the import-export between vprn/grt.

You also need to either do some AS-path modifications, or remove loop prevention based on AS-path since 0.0.0.0/0 learned on R1 via VPRN from R2 will have an as-path like; AS-vprn AS-a AS-B.
R1 will reject the route when it detects its own as-number in the path.

The easiest (and cleanest) way, if possible, is to enable ipv4 on the iBGP connection between R1 and R2.
Then it should work like you want without additional configuration.