[toast0]

The goal of BGP or other routing protocol isn't consensus though. Each router really just wants to find a next hop for every destination, and there are lots of reasons for differences.

In the case where there are multiple next hops to choose from, it might be nice to have some sort of quality metric to decide, but that's really tricky to measure and integrate. It's really outside the scope of BGP.

You would need to instrument packet loss or transfer speed or something like that by destination path on your application servers (or load balancers), and be able to adjust the proportion of traffic through various paths; keeping in mind that you can't really influence the path beyond your routers or the return path.

It's a lot of work, and I don't think the tools are built for it, but I would love to work on it for someone though. I did something similar for SMS routing, but that's a ton easier, fewer choices, less traffic, clearer success, etc.