【作者】 陈忠；

【导师】 苏俭；

【作者基本信息】 电子科技大学 ， 工程硕士（专业学位）， 2017， 硕士

【摘要】 随着互联网的飞速发展,网络中业务种类日益增多,不同种类业务对服务质量(Quality of Service,QoS)的需求各不相同。然而,传统数据报网络对所有的业务都只提供尽力而为的服务。这使得在拥塞的情况下,网络很难保障不同业务的不同QoS需求。软件定义网络(Software Defined Network,SDN)作为一种新型网络,它解耦了传统网络中的控制层和转发层,使得控制层能获取全网拓扑视图并集中控制转发层的行为,为业务数据流提供灵活的QoS保证,这为QoS的研究提供了一个新思路。本文利用SDN网络可编程、易扩展以及有较强的网络管控能力等特点,研究SDN网络中的QoS控制技术,主要工作有:1)对四种不同种类业务进行了等级的区分,并设定不同等级值,在此基础上,提出了SDN网络中区分业务优先级的QoS控制框架,对最高优先级业务进行动态QoS路由,对其他等级业务进行以跳数为代价最短路径算法的路由,使用队列调度管理区分保障不同等级业务的QoS;2)以链路拥塞率、路径跳数为代价,路径时延为约束条件,对最高优先级业务使用拉格朗日松弛聚合代价(Lagrange Relaxation Based Aggregated Cost,LARAC)算法进行动态QoS路由,以保障最高优先级业务端到端的时延;3)提出了基于优先级队列(Priority Queue,PQ)调度算法、差额加权轮询(Deficit Weighted Round Robin,DWRR)队列调度算法和加权随机早期检测(Weighted Random Early Detection,WRED)队列管理算法的队列调度管理策略,进行不同优先级业务的区分调度管理;4)改进了OpenFlow协议,使得OpenFlow协议能支持队列命令,以对队列调度管理策略进行灵活配置。本文对QoS控制框架的拓扑管理模块、网络监测模块、路径计算模块、路由管理模块、队列代理模块和流量管理模块分别进行了实现,并在搭建的真实SDN网络中,对QoS控制框架进行了功能和性能测试。实验结果表明,QoS控制框架能对最高优先级业务进行动态QoS路由,较好地保证了最高优先级业务端到端的时延,并区分保障了不同等级业务的QoS,同时还提高了网络的吞吐量和带宽的利用率。更多还原

【Abstract】 With the rapid development of the Internet,the service types in the network are even increasing,it is different for demand for Quality of Service(QoS)in different types of services.However,traditional datagram network only provides a best-effort service.This makes it difficult to protect the different QoS requirements of different services in the case of congestion.The Software Defined Network(SDN),as a new type of network,decouples the control layer and forwarding layer in the traditional network,so that the control layer can obtain the whole network topology view,achieve centralized control of the forwarding layer behavior,and provide flexible QoS guarantee for the service data stream.It provides a new way for the research of QoS.This paper taking full advantages of SDN,which is programmable,easy to expand,and has strong network control capabilities,studies QoS control technology in the SDN.The main work are as follow: 1)Set different grade values on the four different types of services,propose a QoS control framework which distinguishes the service priority in the SDN,carries on the dynamic QoS route to the highest priority service and the shortest path algorithm route to the other level services at the expense of the hop;2)Use the QoS routing algorithm based on Lagrange Relaxation Based Aggregated Cost(LARAC)for the highest priority service at the cost of link congestion rate and hop count and in the condition of time delay constraint.3)Propose queue scheduling and managing strategy based on Priority Queue(PQ)scheduling algorithm,Deficit Weighted Round Robin(DWRR)queue scheduling algorithm and Weighted Random Early Detection(WRED)queue management algorithm,which can differentiate the scheduling management for different priority services.4)Improve Open Flow protocol to enable it to support queue control commands that can flexibly configure queue scheduling and managing strategy.In this paper,the topology-controling module,the network-monitoring module,the path calculation module,the routing management module,the queue agent module and the traffic management module of the QoS control framework are implemented respectively.In the real SDN,the function and performance of the QoS control framework are tested.The experimental results show that the QoS control framework can dynamically carry on QoS route to the highest priority service,which can guarantee the end-to-end time delay effectively and the QoS of different levels of service differentially and improve the throughput of network and the utilization of bandwith.更多还原