The Research Of Content Swapping-or-reversion Cooperative Caching In Information-centric Networks

With the arrival of Internet wave, people increasingly rely on the network,the traditional host-oriented network architecture has been encountering a series ofchallenges, including great delay in network access process caused by trafficoverloaded which is common situation; on the other hand, although there are largenumber of redundant data in network but the reusing probability remain quitesmall. As the next generation of Internet, Information-centric networking (ICN) notonly names data mechanism but also provides a built-in cache function forthe router, so as to enhance the reusability of content.This paper mainly focuses on the cache content strategy problem of the ICN.The cache copy in ICN’s node can reduce the request delay; at the same time also canlessen the access pressure of the service source node. The traditional cachereplacement mechanism of single node, such as LRU (Least Recently Used) andLFU (Least Frequently Used), cause a large number of redundant content in eachnode when applied in ICN, due to considering only the current node situation, whichresults in low cache utilization rate. Meantime, network information access has cold/hot phenomenon, content of temporarily low attention will become popular aftera period, and then its attention gradually fades after a period. These dynamicchanges have brought difficulty to cache allocation. This paper proposesa swapping-or-reversion cache policy to dynamically adjust the distributionof content.First of all, this paper designs different lifetime for the cache content. In oneaspect we set lifetime for the content by the request frequency of content and thedistance between cache or source node. The farther the distance is, the content of highaccess frequency should enjoy a longer survival time. On the other hand content beinghit many times already cache in downstream to relatively large extent; thispaper comes up with an appropriate attenuation method for the lifetime of this sortof contents.Secondly, due to the level of ICN caching, each node’s statistical frequency arenot the same, and they affect each other. According to the characteristics of ICN, thispaper proposes a mode to update the content frequency collaboratively in networks,and uses this frequency to select worth-caching content and calculate thecorresponding lifetime. Finally, after completing the preprocess of cache content, swap the popular content in the upstream with content being taken outin downstream according to the information maintained between nodes; at the sametime when there are cache space in the upstream nodes, we can also put back thecontent being taken out in downstream to upstream nodes to make the contentallocation reasonable.Observed from the experimental simulation results, the swapping-or-reversioncache policy proposed in this paper can make full use of link length, keepthe diversity of the cache contents, and reduce the costs of network access as well.