内容发布订阅中支持订阅覆盖的事件丢失检测和恢复算法研究

The Research of Event-loss Detecting and Recovery Algorithm in Content-Based Publish/Subscribe Supporting Subscription Covering

基于内容的“发布／订阅”系统通过考虑订阅问的覆盖关系，使得某些订阅不需要转发给所有代理，从而可以减少中间代理的路由表大小，但是由于链路失效、拓扑重配置等原因，某些订阅者可能收不到事件消息，已有事件丢失检测算法都假设每个订阅必须转发给了所有代理，无法支持订阅覆盖的路由，本文提出了一种支持订阅覆盖的概率事件丢失检测和恢复算法，并通过模拟验证了该算法的有效性．

Subscription-cover relationship has been proposed to reduce the size of routing table in intermediate broker in content-based publish/subscribe, in which each subscription needn＇t be forwarded to every broker. Due to link failure or topology reconfiguration, some subscribers cannot receive all event messages. Known algorithms assume that each subscription is forwarded to all brokers,which can＇t support the routing based on subscription-cover. We present a probabilistic event-loss detecting and recovery algorithm that supports subscription covering routing, and its effectiveness is validated through simulation.