Cycloid: A constant-degree and lookup-efficient P2P overlay network

There are many structured P2P systems that use DHT technologies to map data items onto the nodes in various ways for scalable routing and location. Most of the systems require O(log⁡n)O(log⁡n) hops per lookup request with O(log⁡n)O(log⁡n) neighbors per node, where n   is the network size. In this paper, we present a constant-degree P2P architecture, namely Cycloid, which emulates a cube-connected cycles (CCC) graph in the routing of lookup requests. It achieves a time complexity of O(d)O(d) per lookup request by using O(1)O(1) neighbors per node, where n=d×2dn=d×2d. We compare Cycloid with other two constant-degree systems, Viceroy and Koorde in various architectural aspects via simulation. Simulation results show that Cycloid has more advantages for large scale and dynamic systems that have frequent node arrivals and departures. In particular, Cycloid delivers a higher location efficiency in the average case and exhibits a more balanced distribution of keys and query loads between the nodes.