On Tue, 17 Feb 2026 17:48:54 +0100
Ondrej Zajicek <[email protected]> wrote:
> On Tue, Feb 17, 2026 at 05:23:50PM +0100, Mariusz Gronczewski wrote:
> > I have dug some more and tried to change network interface setting
> >
> > on 10.30.1.0/31 RFC 3021 link (no broadcast), doesn't propagate
> > route on 10.30.1.1/30 link, doesn't propagate routes
> > on 10.30.1.1/29 link, propagates routes just fine
> >
> > Similar setup "just works" in FRR so I'm now very confused on what
> > is happening.
> >
> > Setup is 3 devices (other router and core L3 switches) all with
> > separate VLAN and /31 assigned to it.
>
> Hi
>
> Isn't that just mismatched ptp/broadcast mode? BIRD defaults to ptp
> mode for /30 and similar networks, but i thought that in mismatch
> mode it would not even make an adjacency. But perhaps it makes
> adjacency, just not work correctly.
>
> Try setting explicitly broadcast mode (or ptp mode on the other side).
>
First, thanks for help, I didn't thought about trying to change stuff
on the router/switch side ("it was working fine before") and forcing
Juniper/Brocade side to PtP was enough.
I tried every option on Bird side, didn't help, setting
it to p2p on the router/switch side worked, but I'm more confused than
before because:
* the other devices talked between them just fine (in similar /31 vlans
without PtP being explicitly set)
* the same setup in FRR worked just fine (not needing to set PtP there
too)
* the same setup with 2 Bird instances (albeit thru wireguard tunnels)
also works fine (PtP mode is enabled automatically)
It just... established connection, filled the LSADB then refused to
propagate it further
Cheers
Mariusz
--
Mariusz Gronczewski (XANi) <[email protected]>
GnuPG: 0xEA8ACE64
https://devrandom.eu
