Multiple ebgp neighbours to the same peer

[Alexander Zubkov]

Hi,

I had the same issue some time before. I agree that this lock is too
restrictive. Because in some cases you cannot change remote IP or port. I
tried to make 2 multihop sessions to a remote bgp monitoring service. And
its IP is fixed for me and cannot be changed.

On Sat, Jan 21, 2023, 19:49 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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