Resource discovery in a Grid system: Directing requests to trustworthy virtual organizations based on global trust values

This paper studies the resource discovery problem in a Grid system, in which global trust values play a crucial role. The proposed mechanism suggests that routers and resources comprise virtual organizations (VOs) within a Grid system, where a router controls locally a number of resources in each virtual organization. Global trust values are assigned to the system’s VOs. These trust values show whether a VO and subsequently its local resources are trustworthy or not. Our primary goal is to discover the appropriate resource for a specific request and then effectively direct this request to a trustworthy VO that controls locally the appropriate resource. Furthermore, the trust-aware resource discovery mechanism also manages the cases of dynamic changes in the trustworthiness of VOs. For instance, VOs that in the past were untrustworthy could now be trustworthy. The proposed mechanism is capable of detecting these dynamic changes, so that the directing of requests occurs in an up-to-date way. Finally, this paper presents the performance evaluation of the proposed trust-aware resource discovery mechanism by providing a number of simulation tests in Grid systems of different sizes.