A Decentralized Policy Coordination Facility in OpenWebServer

The system adaptability is one of the most important capabilities required for a next generation open system. Many research efforts have developed adaptable systems that allow various applications to meet their specific requirements by combining different policies. However, the policy coordination is still problematic. Fine-grained policies are sometimes not orthogonal, but often have complex constraint dependencies with each other. This paper describes the principles for sophisticated policy coordination, and then presents our coordination facility designed to be used in OpenWebServer, our adaptive web server. Our method is inspired by the natural immune system, a truly autonomous and decentralized system, and coordination facility is developed with iNet, which is a framework for building an artificial immune network. This facility can relaxes constraints between policies and determine the most appropriate set of policies for a given system condition. The coordination process is performed through decentralized interactions among policies without a single point of control, as the natural immune system does.