In my opinion, I don't think the "path" should be the element we should identify. Rather, I think we should identify "forward flows" and "backward flows" (what we call uniflows in our deconinck draft) and see paths as a combination of a forward flow and a backward one.
Maybe - it sounds appealing. But if the client is always responsible for probing paths also for different server announced endpoints, then both endpoints are naturally coupled. The alternative would be for the server to also probe paths, and that can be difficult with NATs without STUN. There are many things to consider ... Mikkel
