CLTChord: Improving lookup at the Chord protocol using cache location table

Peer-to-peer networks have emerged as a common method for sharing large amounts of data. The main challenge in these networks is efficiently locating information distributed across the hosts/peers of the network by decentralized approach. In this paper, first we refer to the Chord protocol that is a distributed lookup service, and then propose a new method, called CLTChord, to optimize this protocol. In this new method, in addition to using the local finger tables for routing requests, the cache location tables are used, in which each node stores nodes which are at its close geographical range. When a node receives a new request, it first checks its cache location table and if a desired response is not received, the algorithm continues to work like the basic Chord protocol. Our simulation shows that this optimization improves the parameters of the hop count, the lookup latencies and number of the sent packets; In this paper, hop count is the distance between the source node which initiates the lookup and the target node which has the desired value; and latency is the duration of time needed for resolving file lookups from the time when it was initiated until it was responded to (measured in milliseconds).