QoS Aware Services Discovery in a P2P Grid Environment

In recent years, grid systems and peer to peer networks are the most used solutions to achieve the same goal: sharing resources and services in heterogeneous, dynamic, distributed environments. Grid systems have well defined middleware, able to assure trust among participants, but they are not totally scalable and they have low fault tolerance. On the other hand, with their decentralized model, P2P systems are more scalable and fault tolerant than grid systems, but they do not have concrete solutions for issues related to security or credential management. Many studies have proposed hybrid approaches that try to conjugate the advantages of the two models. This paper proposes an architecture that integrates the P2P interaction model in grid environments, so as to build an open cooperative model wherein grid entities are composed in a decentralized way. In particular, this paper focuses on a QoS aware discovery algorithm for P2P Grid systems, analyzing protocols and explaining techniques used to improve its performance.