MEDYM: Match-early with dynamic multicast for content-based publish-subscribe networks

Design of distributed architectures for content-based publish-subscribe (pub-sub) service networks has been a challenging problem. To best support the highly dynamic and diversified content-based pub-sub communication, we propose a new architectural design called MEDYM - Match-Early with DYnamic Multicast. MEDYM follows the End-to-End distributed system design principle. It decouples a pub-sub service into two functionalities: complex, application-specific matching at network edge, and simple, generic multicast routing in the network. This architecture achieves low computation cost in event matching and high network efficiency and flexibility in event routing. For higher scalability, we describe a novel approach to extend MEDYM to a hierarchy structure called H-MEDYM, which effectively balances the trade-off between event delivery efficiency and server states maintenance. We evaluate MEDYM and H-MEDYM using detailed simulations and real-world experiments, and compare them with major existing design approaches. Results show that MEDYM and H-MEDYM achieve high event delivery efficiency and system scalability, and their advantages are most prominent when user subscriptions are highly selective and diversified.