CCN中选择性缓存机制的研究

Selective Caching in Content-Centric Networking

现有Internet架构存在着众所周知的缺点,未来网络架构的研究成为了热点.其中,CCN(Content-Centric Networking)在众多新架构中正逐渐被大家认为是最有前途的方案之一,它要求网络中的每一节点都要有缓存功能.所以,研究高效的缓存机制就成为实现CCN预期目标的关键.针对CCN现有缓存机制中存在的"无序缓存"的问题,文中提出了选择性缓存机制SC(Selective Caching).它根据用户的潜在需求和内容的流行规律,只在必要的节点上选择性地(而不是沿着内容传输路径处处地)缓存.同时,采用带宽换缓存的思想,利用链路的冗余带宽,将内容分流到相邻节点缓存,进一步提升缓存效率.我们首先提出了缓存空间消耗的理论分析模型,然后在多种实验条件下对SC进行了验证,实验结果表明SC可以提高网络的缓存效率和性能,同时SC的通信、计算、状态记忆等额外开销也都很小.

Addressing the well known challenges of current Internet, great expectations are held on Content-Centric Networking （CCN）. In CCN, in-networking caching is the key difference from other Internet architectures, so the researching of efficient caching strategy becomes increasingly attractive but remains some great challenges. To address the disorderly caching of current caching strategy, this paper proposes a novel scheme--Selective Caching （SC）. In SC, following the consumer＇s potential demand and the rise and fall of content popularity, content is cached only by some necessary nodes instead of all nodes on the content transmission path. At the same time, in accordance with the bandwidth for-cache, content can be pushed to the adjacent node with more cache. We firstly propose a theoretical model to evaluate cache size consumed. Finally, we evaluate the proposed scheme through extensive simulation experiments in terms of a wide range of performance metrics. The experiment results show that our proposed scheme can yield a steady improvement of network performance and caching efficiency over diverse operating environments. At the same time, SC buys caching performance improvement with negligible overhead.