A Scalable and Self-adapting Notification Framework

There has been a great interest in publish/subscribe systems in recent years. This interest, coupled with the pervasiveness of light-weight electronic devices, such as cellular phones and PDAs, has opened a new arena in publish/subscribe networks. Currently, many broker overlay networks are static and rarely change in structure. Often, a network overlay structure is predefined or manually modified. We present a dynamic broker network for disseminating XML data. Our work builds upon previous network optimization research on ad-hoc publish/subscribe networks. Our framework utilizes user-defined cost functions to satisfy quality of service (QoS) constraints. We reduce the broker network optimization problem to an incremental search problem to generate low cost network configurations with respect to the provide cost functions. We also address certain reliability issues by providing a scheduling algorithm to selectively retransmit information and handle broker connectivity failures.