面向多自治域环境的ICN缓存策略与机制研究

发布时间：2018-08-19 06:27

【摘要】：近年来,流媒体业务及多媒体内容分享应用出现,而新应用更关心内容本身,对内容存储位置并不在意,当前TCP/IP基于主机的通信模式难以适应这一转变,网络流量呈现爆炸性增长的趋势。研究界提出的信息中心网络(ICN,Information CentricNetworking)以信息为网络主体,使用内容名进行数据标识与路由,利用泛在的网络内置缓存和灵活的路由转发引擎来满足用户请求。缓存是ICN网络架构的基石,其呈现的透明化、泛在化和细粒度等特性使之成为解决流量爆炸性增长的主要手段,是ICN网络的一大研究热点。但是泛在缓存的线速响应要求导致节点的缓存容量受限,因此选用合适的缓存策略对于合理利用缓存、提高数据获取速度有重要意义。ICN网络商业化进程要求其适应于多域环境,当把ICN拓展到多个自治域时,缓存成为网络提供商进行商业谈判的筹码,因此多域缓存策略的设计目标转变为符合域间商业关系、有效部署网络缓存、灵活设置策略和较好的用户体验,给缓存策略的研究提出新的挑战。本文以ICN网络的缓存机制作为切入点,分别对ICN网络单域环境和多域环境下的缓存策略进行了研究。主要贡献有以下三点:第一,在对单域环境下缓存策略的分析和比较的基础上,本文提出了基于节点角色划分的混合型缓存策略。将域内节点根据重要性进行角色分配,核心节点采用基于HASH的显式协同策略,边缘节点采用LCE和LCD的隐式协同策略,从而在合理利用缓存空间的基础上获得较好的用户体验。第二,当前缓存策略的研究大多集中在单域,而ICN网络商业化的推进要求其必须适用于多域环境,并符合各网络参与者之间的商业关系。本文提出符合域间商业关系的完备的ICN缓存策略,包括基于自治系统间关系(relation)、基于内容提供商费率(provider)及综合考虑自治域关系和内容提供商费率(relvider)的缓存策略,各自治域可根据自身需求灵活选取不同缓存策略,同时各缓存策略又细分为域间缓存决策、域内缓存决策、域内缓存替换,并设计了与缓存策略相匹配的请求转发策略和通告策略,以满足多域环境下的商业关系和用户需求,并达到合理利用缓存、获得较好网络性能的目标。第三,本文扩展与改进了 ICN中具有代表性的CCN网络架构,对ccnSim仿真框架进行修改,实现了基于节点角色划分的混合型缓存策略和符合域间商业关系的多域缓存策略,并通过仿真实验将所提策略与对比策略进行比较,验证了策略有效性并进行了性能比较。
[Abstract]:In recent years, streaming media services and multimedia content sharing applications have emerged, but the new applications are more concerned about the content itself and do not care about the location of content storage. The current TCP/IP host-based communication mode is difficult to adapt to this change. Network traffic shows an explosive growth trend. The information center CentricNetworking proposed by the research community uses information as the main body of the network, uses the content name for data identification and routing, and makes use of the ubiquitous network built-in cache and the flexible routing forwarding engine to satisfy the user's request. Cache is the cornerstone of ICN network architecture, and its features such as transparency, ubiquity and fine granularity make it the main method to solve the explosive growth of traffic, and it is a research hotspot of ICN network. However, due to the requirement of line speed response of ubiquitous cache, the cache capacity of nodes is limited. Therefore, it is important to select appropriate cache strategies for reasonably utilizing cache and improving the speed of data acquisition. The commercialization process of ICN network requires it to be adapted to multi-domain environment. When ICN is extended to multiple autonomous domains, cache becomes a bargaining chip for network providers to negotiate business. Therefore, the design goal of multi-domain cache policy is changed to conform to inter-domain business relationship, and to deploy network cache effectively. Flexible setting strategy and better user experience present a new challenge to the research of cache policy. In this paper, the cache mechanism of ICN network is taken as the breakthrough point, and the cache strategies in single domain environment and multi domain environment of ICN network are studied respectively. The main contributions are as follows: first, based on the analysis and comparison of cache policies in single domain environment, this paper proposes a hybrid caching strategy based on the partitioning of node roles. The core node adopts explicit cooperative strategy based on HASH and the edge node adopts implicit cooperative strategy of LCE and LCD so as to obtain a better user experience on the basis of reasonable use of cache space. Secondly, most of the current research on cache strategy is focused on single domain, and the commercialization of ICN network requires that it be applicable to multi-domain environment and conform to the business relationship among network participants. This paper proposes a complete ICN caching strategy that conforms to the inter-domain commercial relationship, including the caching strategy based on the content provider rate (provider) based on the autonomous system relationship (relation), and the integrated consideration of the autonomous domain relationship and the content provider rate (relvider). Each local domain can flexibly select different cache strategies according to its own requirements. At the same time, each cache policy can be subdivided into inter-domain cache decisions and intra-domain cache replacement. A request forwarding policy and a notification policy matching the cache policy are designed to meet the business relationship and user needs in multi-domain environment and to achieve the goal of reasonably utilizing cache and obtaining better network performance. Thirdly, this paper extends and improves the representative CCN network architecture in ICN, modifies the ccnSim simulation framework, implements a hybrid caching strategy based on node role partitioning and a multi-domain caching strategy that conforms to the business relationship between domains. The simulation results show that the proposed strategy is effective and the performance is compared.
【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP393.0

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