Merging multiple routes into a single multipath route

[Nico Schottelius]

Hey Jo,

that is a very interesting and repeating use-case that exists for ... as
long as routing exists?

While I am not sure how I'd solve it with bird, it is probably easy to
solve it statically:

- the next hop (default gateway) in these scenarios are often static
- thus you can easily just create the static route with both gateways
  once (ip route add  default nexthop ..) and be done with it

Alternatively you could Linux VRF with your dhcp client, add the default
routes into a separate table (let's say 101 for the first upstream, 102
for the second upstream) and then use bird to read the routes and write
a new merge route.

HTH,

Nico

Johannes Erwerle <jo+bird at swagspace.org> writes:

> Hello.
>
> I am running a setup with 2 uplinks which both have dynamic addresses
> (via DHCP) and NAT and a Linux router. So I get 2 default routes via
> DHCP.
>
> I would like to use both uplinks via the linux multipath routing and I
> am searching for a way to "merge" both default routes that I get into
> one route with multiple next hops.
>
> Is there a way to accomplish that with bird? (or any other tool?)
>
> All of this is only relevant for IPv4.
>
> Greetings
> Jo


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