Thanks for your answer.

The switches weren't properly configured. 

I managed to get multipath working. At least with ipv4.

When enabling "add paths" on ipv6 channel, I get an "Received: Invalid OPEN message" error (although the switch is advertising the capability). I wont blame bird yet, as ExaBGP peers dont care at all.

to be continued ...

Arnaud Houdelette-Langlois
Administrateur des infrastructures systèmes et réseaux
Normandie Université
+33 2 31 56 69 54
Le 04/03/2023 à 00:29, Hugo Slabbert a écrit :
What's your `show protocols all` output for the BIRD side for the sessions with the switches, to confirm BIRD is advertising add-path TX and the switches advertising add-path RX? Do you see ADD-PATH capabilities showing up properly both on the local and neighbor capabilities (TX for local capabilities;  RX neighbor capabilities (switches)?)

On Fri, Mar 3, 2023 at 7:49 AM Marek Zarychta <zarychtam@plan-b.pwste.edu.pl> wrote:
W dniu 3.03.2023 o 16:27, Arnaud Houdelette-Langlois pisze:
> That's was an expected one, but as I send routes to another router and
> not to the kernel i would have expected that this would not have been
> an issue. I will try to update bird.
I might be wrong and misleading you then. Perhaps someone from BIRD
developers can shed more light on this, but if you can give try building
2.0.12 with netlink support.
> Do you know if BSD port is up to date ?

No, it's still 2.0.11 in ports, but you can use the patch from
bugzilla[1]. You'll need the most recent 13-STABLE or 14-CURRENT built
or 13.2-RC1 to build and run netlink flavor or the port.

[1] https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=269553

--
Marek Zarychta