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Same BGP AS usable in disconnected Internet Networks?

will
Level 3
Level 3

Hello, I have a scenario to explore, regarding using the same AS number for a different deployment of BGP. I will simplify it for discussion.

Scenario: Two routers, one at each internet-connected site, both running BGP to the ISP, using the same AS number. These routers are running different “internal” /24 networks, which will be announced to the internet. These two routers are _NOT_ connected to each other via some sort of backbone, or private WAN circuit. Can I use the same AS number for both BGP deployments? Any config guidance you can provide is appreciated.

NOTE: Internal networks = public network local to each sites internet presence.

Thx,

WR

1 Reply 1

Danilo Dy
VIP Alumni
VIP Alumni

Yes you can use same ASN for two sites with different network.

If you want both sites to reach each other thru internet;

1. If you are receiving full routes from your ISP, you have to configure them with the "allowas-in".

2. If you only received default route from your ISP, it should be fine.

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