BGP with ECMP and weight control

[Nigel Kukard]

On 11/19/20 4:06 PM, Alexander Demenshin wrote:
> Hi,
>
> I have two uplinks (different AS), and one is more stable/preferred,
> but when "merge paths" is set to on, all routes are generated with
> weight 1:
>
> 5.21.41.0/24 proto bird
>         nexthop via 10.16.0.1 dev uplink1 weight 1
>         nexthop via 10.17.0.1 dev uplink2 weight 1
>
> Is there any way to adjust weight for ECMP generated from BGP sessions?
>
> I could not find any option/attribute when it is related to BGP or kernel
> protocol, while it is possible for OSPF and static protocols (to a
> degree).
>
> Adjusting local preference or med (in BGP) does not really help - weight
> is unchanged, though of course I could force routes from specific AS
> to be preferred, but then I lose ECMP and if preferred session is dropped
> it takes time to restore connectivity.
>
> Thank you! 


I'd just like to say I'm very interested in this aswell, it would be an
amazing feature to have.


-N