Title: Reciprocity and Barter in Peer-to-Peer Systems.

Speaker: Daniel S. Menasche, UMass

Abstract:

Our  work investigates reciprocity in peer-to-peer
systems. The scenario is one where users arrive to the network
with a set of contents and content demands. Peers exchange
contents to satisfy their demands, following either a direct
reciprocity principle (I help you and you help me) or indirect
reciprocity principle (I help you and someone helps me). First, we
prove that any indirect reciprocity schedule of exchanges, in the
absence of relays, can be replaced by a direct reciprocity schedule,
provided that users (1) are willing to download undemanded
content for bartering purposes and (2) use up to twice the
bandwidth they would use under indirect reciprocity. Motivated
by the fact that, in the absence of relays, the loss of efficiency due
to direct reciprocity is at most two, we study various distributed
direct reciprocity schemes through simulations, some of them
involving a broker to facilitate exchanges.

This is joint work with Professors Don Towsley and Laurent Massoulie.