NDN网络中缓存策略的研究

发布时间：2018-04-15 19:45

本文选题：命名数据网络 + LCE缓存策略　；参考：《北京邮电大学》2017年硕士论文

【摘要】：NDN是一个以内容为中心的网络,其设计之初是解决网络现有IP网络在应用层和网络层关注点不匹配的问题。现在的应用层大多关注的是内容本身,而网络层关注的是内容在哪里。NDN的出现解决了这种不匹配,其将网络层关注点变为内容,使网络层和应用层关注点统一为内容本身,避免了应用程序需要一个中间件来解决关注点不匹配的问题,提高了网络配置和传输效率。在NDN中,一个重要特点是利用网络内缓存技术来提高网络的性能。每一个节点都能够缓存经过数据包,当再次有相同的数据请求时,可以直接从节点缓存中返回。目前的NDN中采用LCE作为其默认的缓存策略,所有路由节点都会存储经过它的所有数据包。当缓存空间满时,就替换最近没有被命中的数据包。LCE缓存策略在网络上造成了大量的数据冗余,降低了整个网络缓存数据的能力,进而影响到网络系统整体性能。本文提出了一种改进NDN缓存策略的方法。该方法针对LCE缓存策略在全网的冗余度较高以及核心节点命中率较低的问题,在缓存策略的决策依据上进行改进,设计了一种基于数据包跳数的缓存策略:Path-LCE缓存策略。该策略结合了 LCE策略和路径协同策略的各自的优点来对内容进行缓存。在核心路由节点使用路径协同策略高效利用节点缓存空间,在边缘路由节点使用LCE策略提高内容传播速度。使得默认的NDN网络在减少了网络内容冗余的同时提高了核心节点缓存命中率,优化了 NDN网络缓存功能。本文在NFD上实现了 Path-LCE缓存策略,并使用ndnSIM进行缓存策略模拟仿真和VMware ESXi上进行部署试验。结果表明,本文提出的Path-LCE缓存策略较LCE缓存策略可以有效的提高核心节点的缓存命中率和降低内容的冗余,并且可以很好的应用到真实NDN环境中,为NDN缓存策略的进一步的研究和部署提供了有效支撑。
[Abstract]:NDN is a content-centered network, which is designed to solve the problem of the mismatch between the application layer and the network layer in the existing IP network.At present, most of the application layer is concerned with the content itself, while the network layer is concerned with where the content. NDN appears to solve this mismatch, it turns the network layer concerns into content, so that the network layer and application layer concerns are unified into the content itself.It avoids the application needs a middleware to solve the problem of mismatch of concerns, and improves the network configuration and transmission efficiency.In NDN, an important feature is the use of intra-network caching technology to improve network performance.Each node can cache the passing data packet and return it directly from the node cache when the same data request occurs again.In current NDN, LCE is adopted as its default cache policy, and all routing nodes store all packets passing through it.When the cache space is full, the packet. LCE cache policy that has not been hit recently results in a large amount of data redundancy on the network, which reduces the ability of the whole network to cache data, and then affects the overall performance of the network system.This paper presents a method to improve NDN cache policy.Aiming at the problems of high redundancy of LCE cache policy in the whole network and low hit rate of core nodes, this method improves the decision basis of cache policy, and designs a cache policy: Path-LCE cache policy based on packet hops.This strategy combines the advantages of LCE policy and path collaboration policy to cache content.The core routing node uses the path cooperation strategy to efficiently utilize the node cache space, and the edge routing node uses the LCE policy to improve the content propagation speed.The default NDN network not only reduces the redundancy of network content, but also improves the cache hit ratio of core nodes, and optimizes the cache function of NDN network.In this paper, we implement the Path-LCE cache policy on NFD, and use ndnSIM to simulate the cache policy and test the deployment on VMware ESXi.The results show that the proposed Path-LCE cache strategy can effectively improve the cache hit rate of core nodes and reduce the redundancy of content, and it can be applied to the real NDN environment.It provides an effective support for the further research and deployment of NDN caching strategy.
【学位授予单位】：北京邮电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP393.0

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