内容中心网络中基于用户偏好的协作缓存策略

Cooperative caching strategy based on user preference for content-centric network

针对内容中心网络(CCN)中节点默认缓存所有经过的内容,未能实现对内容选择性缓存与最佳放置的问题,提出一种基于用户偏好的协作缓存策略(CCUP)。首先,考虑用户对内容类型的喜好和内容流行度作为用户本地偏好度指标,实现缓存内容的选择;然后,对需要缓存内容执行差异化缓存策略,全局活跃的内容则缓存在重要的中心节点,非活跃内容则按本地偏好度与节点同用户距离层级匹配缓存;最后,实现用户对本地偏好内容的就近获取和全局活跃内容的快速分发。仿真结果表明,相比典型缓存策略(LCE、Prob(0. 6)、Betw),CCUP在平均缓存命中率和平均请求时延方面有明显优势。

Nodes in the Content-Centric Network(CCN)cache all the passed content by default,without selective caching and optimally placing of the content.In order to solve the problems,a new Cooperative Caching strategy based on User Preference(CCUP)was proposed.Firstly,user s preference for content type and content popularity were considered as user s local preference indexes to realize the selection of cached content.Then,the differentiated caching strategy was executed on the content that needed to be cached,the globally active content was cached at the important central node,and the inactive content was cached according to the matching of the local preference and the distance level between node and user.Finally,the near access of user to local preference content and the quick distribution of global active content were both achieved.The simulation results show that,compared with typical caching strategies,such as LCE(Leave Copy Everywhere)、Prob(0.6)(Probabilistic caching with0.6)、Betw(cache“less for more”),the proposed CCUP has obvious advantages in average cache hit rate and average request delay.