+1.
Scoping the way I intend to implement it will require more threads, conceptually 1 thread per scope. Of course, that's not the way I'll implement it, but I;'ll use a thread pool instead. However, if we have 65'000 scopes, then ideally we would have a thread pool which supports up to 65'000 threads. Of course, this is only if we get 65'000 messages, each for a different scope *at the same time*.
I was thinking of reusing the thread pools from the transport, but if a pool has a DISCARD rejection policy, I might be in trouble as a message passed up to SCOPE cannot be discarded as NAKACK or UNICAST consider it delivered, so we won't receive it again !