Managing QoS degradation of partner web services: A proactive and preventive approach

Abstract

In the service oriented paradigm, a software solution is a composition of individual web services. These web services, also called partner services, contribute not only to realize the functional capabilities of the software solution but also determine its Quality of Service (QoS). A partner web service operates in a dynamic environment, and hence is vulnerable to failures, or suffers from QoS degradation. The failure of a partner web service compromises QoS of service based solution. Therefore, a research challenge arises as to how to manage web services which suddenly disappear at the time of execution or stop performing as expected. Several solutions exist for run time monitoring of the partner web services so that when QoS values of some of them degrade, the software solution can be adapted and executed using alternative web services with better QoS. But these solutions are confined either to client side or to provider side. In this paper, we propose a solution which is distributed between the clients and the service providers. It is a software agent based framework that prevents invocation of partner web services with degraded QoS. The experimental results show the effectiveness and efficiency of the proposed solution in a dynamic runtime environment.