Performance Analysis of Web Service Replica Selection in an Extranet

Providing Web service replicas improves the overall system performance and redundancy for hardware failures. In Business-to-Business, this may be particularly interesting for organizations in an extranet. In our previous work, we proposed a broker to perform the web service replica selection. Furthermore we investigated a replica selection algorithm called minU and performed a preliminary analysis comparing random replica selection algorithm in a simple 4-node ring topology. In this paper we present a detailed performance analysis of mini and the factors affecting its performance under a larger 11- node network. The factors are weight given to most recent utility value (p), weight given to communication delay (a) and replica placement to name a few. Results show that the response time achieved using the minU replica selection policy greatly depends on these factors and also on the topology used. For instance, as the weight given to the most recent utility value is increased, the response time of the Web services decreased. In our simulation experiments, choosing a to be 0.3 results in minimum response time.