覆盖网络上基于内容的混合路由方法

A Hybrid Content-Based Routing Protocol in Publish/Subscribe System

内容发布?订阅系统是一种完全解耦的基于事件的中间件系统,能独立地仅依赖消息内容实现事件匹配和路由,提供了更细粒度的匹配和更高的透明性.在现有基于内容的路由协议中,订阅路径上的代理节点需存储所有的订阅以构建路由表,从而通过查询路由表实现事件路由.由于系统的路由计算开销受订阅数目影响,因此无法支持大规模应用.为解决这一问题,提出了一种快速的基于内容的路由协议HCBR(hybrid content-based routing).它采用路标的方式建立路由表,从而避免事件在每个节点都进行基于内容的匹配,极大降低事件匹配开销.实验结果表明,在采用27个节点、订阅数目达到10万级别时,基于HCBR协议的系统代理节点的吞吐量为原系统的10倍;而当事件传输跳数达到27跳时,基于HCBR协议的系统事件端到端传输平均时间缩短到原系统的1?5.

The content-based publish?subscribe system is a completely decoupled middleware which can route messages based on their content rather than destination address,then providing a finegranularity event dissemination and high-level transparency. However,in traditional routing protocol,nodes on publish?subscribe path need to store all subscriptions to construct the routing table which is utilized for routing messages.Since the computational cost of system grows with the number of subscriptions,it cannot be used for large scale applications.We propose a new routing protocol called HCBR which can effectively avoid content-based matching in all nodes on publish?subscribe path by using marks to build the routing table,and finally extremely decrease the cost for matching operations.The experiment results show that when 27nodes are used and the number of subscriptions reaches 100 000,the system based on HCBR has 10times throughput than the traditional system has. And when the publications transmission hop reaches 27,the new systems average publication transmission time is only 1?5comparing to the traditional system.