Multiple ISP Load Balancing

[jof at thejof.com (Jonathan Lassoff)]

The best applications for analyzing paths, that I've seen, have been
in-house development projects. So, admittedly, I don't have much experience
with commercial products for route optimization.

Projects I've seen that analyze "best" paths to Internet destinations via
multiple ISPs add instrumentation to content-serving applications to log
stream performance details to a database or log collection system along
with a timestamp. Another database keeps a periodic log of RIB data that
lists the specific next-hops out of the AS. Another log keeps a running log
of UPDATEs.
>From joining up all of this information, you can figure out the ISP you're
taking to a destination (at a given time) and how the stream performed.
Then, add some logic to inject routes to try out different next-hop ISPs
for some destinations.

Then, compare the newer ISP-path to the older one and see which performs
"best". Where "best" means something specific to your application
(optimizing for latency, cost, etc.)

Cheers,
jof