1 Service Discovery using Volunteer Nodes in Overlapped Clusters for Pervasive Computing Environments

We propose a service discovery architecture called VSD (Service Discovery based on Volunteers) for heterogeneous and dynamic pervasive computing environments. The proposed architecture uses a small subset of the nodes called volunteers that perform directory services to facilitate efficient service discovery. In VSD, stable and capable nodes serve as volunteers whereas relatively dynamic and less capable nodes depend on the volunteers. Thus VSD recognizes node heterogeneity in terms of mobility and capability. We discuss characteristics of VSD architecture and methods to improve connectivity among volunteers for higher discovery rate. By showing that VSD performs quite well in MANET scenarios, we validate our hypothesis that VSD is a flexible and adaptable architecture appropriate for dynamic pervasive computing environments. VSD incorporates several novel features: i) handles dynamism and supports self-reconfiguration; ii) provides physical locality and scalability; and iii) improves reliability and copes with uncertainty through redundancy by forming overlapped clusters