POF-ICN网络中的混合路由机制研究

发布时间：2018-08-04 08:45

【摘要】：因特网的核心功能正逐渐从过去主机互联转变为内容分发方面,由于传统网络对于网络规模膨胀和内容特别是多媒体内容分发有着许多难以解决的限制和桎梏,许多研究人员根据当前网络发展的新需求研究和探索下一代网络架构,其中的研究热点之一就是倡导以信息或内容分发作为网络核心功能的信息中心网络ICN。软件定义网络SDN技术基于网络控制面和数据面分离的原则,使用控制器的集中式视角对域内交换机进行统一管理,可以有效简化网络部署、灵活网络配置方面;而华为提出的协议无感知转发协议POF则在此前的SDN南向接口标准OpenFlow协议基础之上,能够不被传统协议拘束而设计新的网络架构,比如为信息中心网络定义全新的网络协议和包格式等,对于网络研究具有重要意义。信息中心网络的研究重点围绕在其命名、路由、缓存等方面,其中路由可扩展性是信息中心网络能否适用未来网络需求的重要问题,此前很多基于SDN技术实现的ICN网络架构中,多采用基于动态流表的下发、删除来为数据流设定路由路径,然而这种办法引入了不小的处理时延,增加控制器负担和节点内存消耗。本文借鉴了源路由在简化网络状态、提高节点转发效率的优势,并基于对网络对象的新命名方案,提出适用于POF环境的ICN网络的可扩展源路由策略:针对域内和跨域不同场景下的对路由效率和扩展性的性能要求,利用端口栈的策略为域内进行严格路径规划、利用域名匹配静态流表的策略进行域间路由控制。信息中心网络中路由结合缓存的设计对于提升内容分发效率、改善用户体验有很大影响,在可扩展源路由中规划的是从请求源到内容源的最短路径,缓存操作发生在该条路径中,而无法感知附近缓存以及减少缓存冗余等问题。因而本文提出一种针对缓存可感知路由策略,利用哈希分布的办法减少位于网络汇聚层/核心层缓存空间的缓存冗余度、提高该缓存空间利用效率,基于节点协作缓存在节约网络带宽、用户请求时延方面的效益进行缓存决策。最后通过实验证明,可扩展源路由能够能提升系统在控制面和数据面中的路由性能,提升系统的可扩展性。补充了缓存路由策略后的混合路由策略,能够有效减少路由在带宽和时延方面的代价、提高缓存空间利用效率和缓存命中率,改善内容分发效率。
[Abstract]:The core functions of the Internet are gradually changing from the interconnection of hosts to the distribution of content. Because the traditional network has many restrictions and shackles for the expansion of network scale and the distribution of content, especially multimedia content, it is difficult to solve. Many researchers study and explore the next generation network architecture according to the new needs of the current network development. One of the research hotspots is to advocate the information center network ICN which uses information or content distribution as the core function of the network. The software defined network SDN technology is based on the principle of separating the network control surface from the data surface, and the centralized view of controller is used to manage the switch in the domain, which can effectively simplify the network deployment and flexible network configuration. On the other hand, Huawei's protocol, POF, is based on the previous OpenFlow protocol, the standard of SDN's southward interface, and it can design a new network architecture without being bound by traditional protocols. For example, defining new network protocols and packet formats for information center network is of great significance to network research. The research of information center network focuses on its naming, routing, caching and so on. The routing scalability is an important problem whether the information center network can adapt to the future network requirements. Many ICN network architectures based on SDN technology have been implemented previously. The routing path for the data flow is usually set by sending and deleting based on the dynamic flow table. However, this method introduces a lot of processing delays and increases the controller burden and node memory consumption. This paper draws lessons from the advantages of source routing in simplifying the network state and improving the efficiency of node forwarding, and based on the new naming scheme for network objects, An extensible source routing strategy for ICN networks suitable for POF environment is proposed. According to the performance requirements of routing efficiency and scalability in different scenarios within and across domains, the strategy of port stack is used for strict path planning in the domain. The strategy of domain name matching static flow table is used to control inter-domain routing. The design of routing combined with cache in information center network has great influence on improving the efficiency of content distribution and improving the user experience. The shortest path from request source to content source is planned in extensible source routing. The cache operation occurs in this path, but it can not perceive the nearby cache and reduce the cache redundancy. Therefore, this paper proposes a cache perceptible routing strategy, using hash distribution to reduce the cache redundancy in the network convergence layer / core layer cache space, so as to improve the efficiency of the cache space utilization. Based on the benefits of node cooperative caching in saving network bandwidth and user request delay, the cache decision is made. Finally, it is proved by experiments that the extensible source routing can improve the routing performance of the system on the control surface and data surface, and enhance the scalability of the system. The hybrid routing strategy can effectively reduce the cost of bandwidth and delay, improve the efficiency of cache space utilization and cache hit rate, and improve the efficiency of content distribution.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP393.02

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