At first I wasn't sure what a "route optimizer" was supposed to do -- the term is rather generic and could have a lot of different interpretations. A multi-path traffic balancing solution in the style of Cisco's OER has to be tightly integrated with the routing infrastructure. Specifically, it needs first hand BGP peer data in order to work reliably. There will be a number of cases where an add-on solution might be able to improve on certain things, but there is one major hurdle: a BGP speaker only forwards its own best paths, so an add-on analyzer might well never learn about alternative paths. The only way for any implementation to reliably learn (all) alternative paths and otherwise maintain routing integrity is by receiving BGP data first hand, ie directly peer with transit providers and other peers. Best, -- Per