What is this?
Is this meant on routing query hits back to where the query came from, or does this apply to the actual query itself?

I haven't managed to find a lot of information on this matter, so I deceided to ask. One thing that seems to be related are ultra-peers. That's another topic I just can't seem to find any decent information on. I know what it is, but I don't know how to implement it.

Any help on these topics would be highly appreciated