Peer-to-peer Distributed Lookup Services

As we are living in the era of technology innovation, the need of sharing information is becoming more important than ever. Peer-to-peer applications were introduced and developed in order to facilitate particularly the sharing of large video/audio files and software. Although the entire peer-to-peer research literature consists of four divisions: search, security, storage, and applications, in this paper, I will focus on the first division; search method or Peer-to-peer (P2P) distributed lookup service which is one of the most popular Internet applications. There are two types of algorithm in the P2P routing: “structured” and “unstructured”. Gnutella is the typical application for the unstructured approaches in which keywords queries are widely flooded. On the other hand, the structured algorithms which support distributed hash table (DHT) will guarantee location for a target within a determined number of hops. Although DHT did repair some scaling problems in the unstructured approach and has been referred to as the “second generation”, it is inherently ill-suited to range queries which are more prevalent and important in practice. Also, DHT will become inefficient when peers are continually arriving and departing. Therefore, I assert that it is more worthy to retain the simplicity of Gnutella while proposing new mechanisms to improve its scalability than to build a truly scalable DHT.