Multiple ebgp neighbours to the same peer

[Alexander Zubkov]

Hi all,

A quick try to fix the problem. But I'm not sure in complete correctness
though.

On Sat, Jan 21, 2023 at 8:17 PM Prem Anand <h.prem.anand at gmail.com> wrote:

> Hi Ondrej,
> Thanks for your quick reply.
> I tried after adding another ip address to the interface on the FRR side
> and can confirm that both my bgp neighbours came up :)
>
> Unfortunately, my original intention is to peer this with a Brocade
> hardware router, that I don’t have control of. So it is difficult for me to
> add another IP address or bind to a different port.
>
> Given that you feel that the explicit lock is restrictive and unnecessary,
> it would be really helpful, if you could remove that explicit lock when you
> get some time.
>
> Regards
> Prem
>
> On 21 Jan 2023, at 18:43, Ondrej Zajicek <santiago at crfreenet.org> wrote:
>
> On Sat, Jan 21, 2023 at 06:05:16PM +0000, Prem Anand wrote:
>
> Hi all,
> New user here
>
> I am trying to get 2 ebgp neighbours on bird to peer with a remote bgp
> endpoint on frr node.
> One between 10.100.101.1 <—> 10.100.1.1 and other between 10.100.102.1 <—>
> 10.100.1.1
>
>              ┌──────────────────┐                        ┌─────────────┐
> 10.100.101.1 │                  │ensp5s0                 │             │
>       loop1  *     Bird         │◄──────────────────────►┘    Frr      │
>              │     2.0.10       │10.100.1.2          10.100.1.1        │
>       loop2  *                  │                        │             │
> 10.100.102.1 │                  │                        │             │
>              └──────────────────┘                        └─────────────┘
>
>
> I find that only the first ebgp neighbour comes up and moves to
> "Established” state whereas the second ebgp neighbour remains in “Idle”
> state.
> However if I restart the bgp neighbour in “Established” state, the other
> bgp neighbour comes up and moves to “Established” state, but the restarted
> one remains in Idle state.
>
> Is there any limitation that I can’t have 2 neighbours to the same peer?
> Or do I have to ensure that the 2 neighbours use different tables?
>
>
> Hi
>
> Yes, there is an explicit lock for remote IP to be assigned to one BGP
> protocol. You can avoid it by using different IP on Frr side like you use
> on Bird side, or by using pair of non-standard ports (with the same IP).
>
> Thinking about it, the explicit lock seems unnecessary restrictive. If
> the local IP is defined, then the lock should be for (local IP, remote
> IP, ports) pair.
>
> --
> Elen sila lumenn' omentielvo
>
> Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
> OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
> "To err is human -- to blame it on a computer is even more so."
>
>
>
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