针对命名数据网络(Named Data Networking, NDN)存储空间的有效利用和应答内容的高效缓存问题，该文采用“差异化缓存”的方式，提出一种依据内容请求序列相关性的协作缓存算法。在内容请求中，预先发送对于后续相关数据单元的并行预测请求，增大内容请求的就近响应概率；缓存决策时，提出联合空间存储位置与缓存驻留时间的2维差异化缓存策略。根据内容活跃度的变化趋势，空间维度上逐跳推进内容存储位置，时间维度上动态调整内容缓存时间，以渐进式的方式将真正流行的请求内容推送至网络边缘存储。该算法减小了内容请求时延和缓存冗余，提高了缓存命中率，仿真结果验证了其有效性。%How to efficiently utilize the finite storage space and cache content chunks in the content store poses challenges to the caching policy in Named Data Networking (NDN). Using the differentiated caching strategy, a collaborative caching algorithm is proposed based on the request correlation. In the scheme, the subsequent correlated content chunks are requested in advance to increase the hit ratio for content requesting. When making the caching decision, a two-dimensional differentiated caching policy combining the caching location and cache-resident time is proposed. According to the change of content activity, the caching location is pushed downstream hop by hop in the spatial dimension in order to spread popular contents to the network edge in a gradual manner, and the cache-resident time is adjusted dynamically in the time dimension. The simulation results show that the proposed algorithm can efficiently decrease the request latency, reduce the cache redundancy, and achieve higher cache hit ratio than other caching strategies.
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