Chord2: A two-layer Chord for reducing maintenance overhead via heterogeneity

Empirical studies have shown that participating nodes in peer-to-peer (P2P) systems are not equivalent. Some nodes, known as “super peers”, are more powerful and stable than the others. Such heterogeneity has been taken into account in the design of P2P systems in two ways: by employing super peers to serve as index servers for query, and by routing through super peers to speed up query. In this paper, we use super peers to reduce maintenance cost in Chord—a DHT network which, like other DHT-based systems, is often praised for its guaranteed search feature but has relatively higher maintenance overhead than Gnutella-like unstructured P2P networks.