sorted route advertisements from bird bgp session.

[Maria Matejka]

Hello,

On Tue, Apr 07, 2026 at 02:14:40PM -0700, gautham devalapalli wrote:
 
> When advertising the routes from BGP to an nxos switch, we are noticing the
> routes come in random order instead of sequential order.

That's expected.

> Using bird 2.0.8 version.

That's very old.

> Is there a way to force an order of routes like how Ixia traffic generator
> does this.

There is literally no way. We may think of some hacks and quirks how to
immitate that but there is no actual guarantee, and it will work only in
very limited scenarios.

I expect that you wanna use this for traffic-blasting other BGP
implementations, and that is something not really expected from BIRD.
While I admit that I'm using myself a custom-modified BIRD 3 to blast
another BIRD 3 with millions of routes to measure performance,
it's not an officially supported use-case for now.

We are not opposed to implementing traffic-blasting extensions into our
BGP. However, even keeping the send order is hard, and the TX routines
belong to the most complicated parts of BGP. I would expect that there
would be much more one could desire here, and all of that carries quite
some maintenance burden which only grows over time.

In other words, money can fix this.

Until then, you may try starting the static protocol disabled and
enabling it after startup, that should help. But if you wanna get
full-speed blast, you are screwed. Also, you may wanna try the same
scenario with BIRD 3, you may get, paradoxically, more stable results.

Happy route-blasting!
Maria

-- 
Maria Matejka (she/her) | BIRD Team Leader | CZ.NIC, z.s.p.o.
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