基于内容流行度和节点重要度的CCN缓存策略

A Caching Scheme Based on Content Popularity and Betweenness in Content Centric Network

内容中心网络(content centric network,CCN)强调以内容资源本身为中心,CCN网络在路由节点对内容进行缓存,使内容接近用户,因而缓存策略研究成为CCN网络的关键技术之一。传统的主流缓存策略Always(处处缓存)、LCD(leave copy down)都会很大程度上造成节点空间的浪费和缓存内容的冗余。改进的Betw(betweenness)方案仅考虑了节点介数,容易造成两个问题:一是导致最流行的内容只缓存在高介数的节点,无法到达最靠近用户的位置;二是导致高介数的节点缓存更换频繁,流行内容缓存时间短。为了解决这一问题,提出一种内容流行度与节点重要度相结合的缓存机制,实现优化的缓存协作。在ndnSIM平台进行仿真,结果表明该方案提高了路由节点缓存命中率,减小了获取内容的平均跳数。

Content center network（ CCN） emphasizes the content resource itself as the center.CCN network caches the content in the routing node in order to make the content close to the user,so the cache scheme research has become one of the key technologies of CCN network.The traditional mainstream cache strategy like Always（ always cached）,LCD（ leave copy down） will be largely caused by the waste of node space and the redundancy of content.The improved scheme Betwonly takes into account the betweenness,which can lead to two main problems： one is that the most popular content is only cached in the node with the lager betweenness,which can not reach the nearest user position; the other is that the Betwhas the more frequent replacement,which will decrease the time of the content cache in node.For this,we propose a coporate caching scheme considering content popularity and betweenness to realize optimized cache cooperation.The simulation on the ndn SIMplatform shows that the proposed scheme improves the hit rate of the routing node and reduces the average hop count for getting the content.