Apocrypha: Making P2P Overlays Network-aware

Many distributed systems built on peer-to-peer principles organize nodes in an overlay network, in order to enable communication between nodes. In general, this overlay network may have nothing to do with the location of nodes on the physical network. We propose a generic mechanism called Apocrypha to make any P2P overlay “network-aware”, and thus optimize internode communication. We show how Apocrypha adaptively trades off the quality of optimization against the cost of optimization under dynamic conditions. We demonstrate the applicability and utility of Apocrypha on two different P2P systems: the Chord system which uses a deterministic overlay topology, and the Gnutella system which operates on an ad hoc topology. We also describe new, improved routing protocols for the Chord system, and introduce the long-circuit phenomenon in Gnutella.