Apocrypha: Making P2P Overlays Network-aware

Many distributed systems built on peer-to-peer prin- ciples 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 inter- node communication. We show how Apocrypha adaptively trades off the quality of optimization against the cost of optimization un- der dynamic conditions. We demonstrate the applicability and utility of Apocrypha on two different P2P systems: the Chord sys- tem 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 intro- duce the long-circuit phenomenon in Gnutella.