Grid Service Discovery Model Based On Ontology And P2P Techniques

Grid has attracted a wide attention as a new field, and the Grid technology becomes more and more practical after the Open Grid Service Architecture is introduced. With the standard interface-Grid Service, OGSA provides a unified solution for the sharing of geographically distributed resources, and delivers a reliable computing capability that is independent of the computer and its location. All of these bring new challenges to the service discovery.This paper focuses on discovering the Grid service. By analyzing the existent resource discovery model, the paper proposes a Grid service discovery model based on ontology and P2P technology. First of all, it analyzes the characteristics of the existent P2P models, classifies and compares them according to their capabilities. Then the paper gives a two-level P2P search model, combining the distributed search with the centralized management. Each peer node can provide the semantic description of the service and ontology of a specialized knowledge domain. All the service match and discovery are carried out by peer nodes. Each user is exposed as a user agent to do all the operations and the discovery process is totally transparent. In this paper, publish/subscribe method is used to implement service dissemination. Service providers must register their services to peer nodes, and users also need to submit their service requests to peer nodes in order to obtain services. The peer which received the request do the match and discovery work by conducting local and remote processing. The semantic-based match is used to increase the match accuracy and offer the intelligent search. This model is adapted to the complexity, heterogeneous and dynamic of the Grid resources, and has a better expansibility.