Yatin Chawathe

Research Interests
Intel Research Seattle
AT&T Labs Research
Can Heterogeneity Make Gnutella Scale?

Yatin Chawathe, Sylvia Ratnasamy, Scott Shenker, and Lee Breslau

Many researchers have proposed designs for "highly structured" peer-to-peer systems, for example, CAN, Chord, and Tapestry. The underlying philosophy behind these systems is that random searches over "unstructured" P2P networks such as Gnutella are inherently unscalable. Instead, the structured systems tightly control the overlay topology and the layout of files (or pointers to files) across the topology. Unfortunately, doing so makes these systems less resilient to transient user populations precisely because it is difficult to maintain the structured topology in the face of constantly joining and leaving nodes. Moreover, no one has yet demonstrated that these systems, while well-suited for exact-match queries, can support partial match queries such as keyword searching efficiently. On the other hand, unstructured P2P systems like Gnutella can easily answer such queries, and are better suited for handling large transient populations.

In this work, we re-visit the question of whether Gnutella-like unstructured P2P systems can be made more scalable. Our approach is based on recent studies that show that Internet-wide P2P networks demonstrate large degrees of heterogeneity. We leverage this heterogeneity to adapt the topology of the overlay network in a dynamic fashion so that queries across the network are automatically funnelled towards nodes that have the capacity to handle them. In addition, we introduce active flow control to prevent overloading nodes or links between nodes, and improved search techniques to better utilize network resources than the simplistic flooding techniques currently used by Gnutella.

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