Improvement of Routing Structure in P2P Overlay Networks

Although peer-to-peer overlays have been elaborately studied, they still have redundant overheads. Pastry and Chord use leaf sets to connect those nodes contiguous in numerical space, but these pointers have no contribution to efficient routing. In this paper we argue that if the mapping between a message key and its root node is determined in a smart way, leaf sets can be removed, largely decreasing system overheads. We present a novel overlay algorithm derived from Pastry, in which nodeIds have different lengths and form a Huffman set, routing tables have no empty items and root node exactly prefix-matching its keys. By these means, our approach abolishes the leaf sets with no ill effect on routing performance or other properties. Experimental results show that our approach saved about 22~25% messages cost for maintenance from Pastry in an overlay of 10,000 peers.