Achieving bounded delay on message delivery in publish/subscribe systems

Publish/subscribe (pub/sub) systems are very suitable for the dissemination of dynamic information over the Internet. As dynamic information is usually characterized by a short lifetime, both publishers and subscribers may specify the delay requirement on message delivery. Although existing pub/sub systems can easily be extended so that publishers and subscribers can specify their delay requirements, it remains a challenging problem to improve the efficiency of pub/sub systems so that as many messages can be successfully delivered as possible, while the network traffic does not increase significantly. In this paper, we propose an efficient approach for pub/sub systems to achieve bounded delay on message delivery. Three message scheduling strategies are proposed for the system to make use of available bandwidth efficiently. Simulation results show that our strategies enable subscribers to receive significantly more valid messages than traditional strategies, while the network traffic just increases slightly.