Policy Management in Context-Aware Networks

Sammanfattning: The Ambient Network (AN) Project is part of the European Commission’s 6th Framework Programme and aims to enable cooperation between heterogeneous networks, using current and future wireless technologies, minimising the effort of mobile users to gain access to the services that they are interested in - irrespective of their location or the network they are currently using. Because of the highly mobile nature of users and a demand for instant and dynamic access to services, these networks have to be composed ‘on the fly’ without any pre-configurations. The use of context information in AN can remove the need for pre-configuration of networks, hence making them autonomic. However, a concern exists that the free and uncontrolled dissemination of context information could breech the privacy of the participants. It is extremely important to address these privacy issues in order to control who has access to what context information. This control can be achieved through the use of well defined policies. This creates a requirement for a framework in the ContextWare architecture for protecting context information. This masters thesis project is part of an effort to create a policy based infrastructure for authorisation of access to network context information within the AN. The thesis investigates, models, and designs an architecture for a policy management system based on OASIS XACML, that creates an extension to the architecture for management of context information in the AN. In addition to a policy management architecture within an AN, a policy management architecture for composing ANs is also created. To facilitate the transfer of requests and policies, the thesis creates a Policy Management Protocol. The designed architecture was then implemented to create a proof of concept. The designed architecture and protocol were evaluated by running tests on the prototype. The measurements from the tests are analysed and presented in this thesis. The analysis of the experimental data indicates that a policy management system is both feasible and practical. The results show that the delay overhead caused by introducing policy management in a distributed context provisioning system, ranges from 1.7% in a system without load to 6% in a worst case scenario. The throughput of the policy management system is 15 requests per second under load.