Hi Christopher,

Resilient ECMP is not quite BIRD's business in some sence, but kernel's. But on the other hand it needs to tell the kernel about such routes properly. AFAIK resilient ECPM is supported in Linux only with next hop objects, which BIRD does not use now, and FRR does.

Regards,

Alexander Zubkov

On Fri, Feb 20, 2026, 18:32 Christopher Munz-Michielin <christopher@ve7alb.ca> wrote:

Hey all,

Wondering what the state of support for resilient ECMP with BIRD is?
I'm currently using BIRD to send traffic to a number of backend servers
using ECMP, but of course if one server leaves the group, the entire
hash is recalculated which results in clients being potentially directed
to a different server resulting in tcp resets.

I've been reading up on resilient nexthop which seems to solve this
issue, and is supported natively in FRR, but I can't find any
documentation about it's level of support in BIRD. Wondering if anyone
else has had experience with this technology and BIRD.