Partially Decentralised Context Management for P2P Communities

The retrieval of context information is usually limited on a single user. Though some context subscription methods do exist, the mechanisms are not optimised for distributing context information concerning a group of users. This paper presents a context management system that utilises the presence service architecture and user communities on top of P2PSIP network. The system is based on existing IETF standardisation efforts and utilises SIP-based messaging protocols in a novel way to improve management and distribution of community context information. The testing results show that our system clearly outperforms the method of individual subscriptions to context information when the number of members in a community increases. With large communities, the network traffic gain exceeds 60%, whereas the delay decreases to one-quarter.