Bgp Peer with multiples as number

[brietmax]

Hello 

We have 2 sites dc1 and dc2

My network collègue Said me 

On dc1 

Configuré bgp Peer 1.1.1.1 with as number 65010 and second Peer 1.1.2.1 with as 65010 

On dc2 

Configure 

1.1.1.1 with as number 65020

1.1.2.1 with as number 65020

Is it possible 

Regards

[Chandra Morkonda]

This should be possible. You should be able to peer T0 with two BGP peers with same BGP AS numbers despite of them being on different sites. 

[brietmax]

ok so I had configured 

bgp peer

1.1.1.1 as 65010

1.1.1.2 as 6510

when I try to ad 1.1.1.1 as 65020 I had an error bgp peer already exist

I think is not possible

[Andrey Semenov]

Are 65010 and 65020 your ASNs on T0?

[brietmax]

Non my local ADN on the T0 is 65100

The 65010 and 65020 is the remote ASN for the 2 sites 

[Andrey Semenov]

Got it. So you can't, your T0 is 1 logical router, even it is spread over number of edges.

[Chandra Morkonda]

@brietmax

Andrew is correct-you cannot configure the same BGP peer more than once on the same Tier-0 (T0) gateway on a single node, regardless of whether the AS number is the same or different.  

As for your scenario across two data centers:  
- If both DCs share the same underlying physical network, it's feasible to use the same BGP peer IP and ASN across sites.  
- However, if each DC connects to distinct physical network devices, then each peer must have a unique IP, and you'll need to use different BGP ASNs for each site to maintain proper routing separation.

If your question is still unresolved, I highly recommend sharing a network diagram to illustrate your architecture and desired outcome. Even a rough whiteboarding sketch can go a long way-these visuals often bridge communication gaps that text alone can't fill.

--

If your question is addressed the mark it as Best Answer.

[Sachin Bhardwaj]

Agree with Chandra Morkonda and Andrew's comment, as the same BGP peering can't be peered more than once at a T0 Gateway.

Sachin