SDN网络中的故障检测与修复技术研究

【目的】虽然软件定义网络(SDN)是一种开放的架构,但也存在着各类网络错误。为实现SDN的高可用性,对故障检测与修复机制进行研究是至关重要的。【方法】首先,对SDN架构与OpenFlow协议进行分析,总结出SDN网络中可能出现的错误,并设计出数据平面错误检测方法。其次,基于主动修复与被动修复机制,并考虑数据流量服务的质量(QoS)需求,从而提出主动与被动相结合的故障修复机制。在此基础上,本研究设计出基于开源代码的故障检测与修复方法,其使用的是非同步报警机制监测网络,根据故障数量和影响程度选择3种修复模式。【结果】试验结果表明,本研究设计的方法能有效检测出SDN数据平面中常见的错误,在保障QoS的前提下,能最大限度恢复网络功能。【结论】该方法在处理多类故障和考虑QoS需求方面超过现有机制,为SDN高可用性和应用提供理论与实践基础,而进一步提高对复杂故障的处理能力和增强自修复智能性是后续的研究方向。

SDN Based Next Generation Mobile Network With Service Slicing and Trials

Software-Defined Network （SDN） empowers the evolution of Internet with the OpenFlow, Network Virtualization and Service Slicing strategies. With the fast increasing requirements of Mobile Internet services, the Internet and Mobile Networks go to the convergence. Mobile Networks can also get benefits from the SDN evolution to fulfill the 5th Generation （5G） capacity booming. The article implements SDN into Frameless Network Architecture （FNA） for 5G Mobile Network evolution with proposed Mobile-oriented OpenFlow Protocol （MOFP）. The Control Plane/User Plane （CP/UP） separation and adaptation strategy is proposed to support the User-Centric scenario in FNA. The traditional Base Station is separated with Central Processing Entity （CPE） and Antenna Element （AE） to perform the OpenFlow and Network Virtualization. The AEs are released as new resources for serving users. The mobile-oriented Service Slicing with different Quality of Service （QoS） classification is proposed and Resource Pooling based Virtualized Radio Resource Management （VRRM） is optimized for the Service Slicing strategy with resource-limited feature in Mobile Networks. The capacity gains are provided to show the merits of SDN based FNA. And the MiniNet based Trial Network with Service Slicing is implemented with experimental results.

On Effective Virtual Networks Interconnection

The network services today require extremely agile and mobile, however, the traditional IP infrastructures are so rigid that cannot fit services well. A way should be put forward to automate the network to improve responsiveness to change. SDN and network virtualization(NV) are two hottest approaches to make networking more automated and scalable to support virtualized and cloud environments. Network virtualization combines hardware and software network resources and network functionality into a single virtual network. SDN is created to simplify traffic management and achieve operational efficiencies by establish and exercising central control over packet forwarding. In this paper, we focus on the situation where SDN controller needs to connect two virtual networks temporarily. We put forward three algorithms to try to make this connection more effective and evaluate these three algorithms.

A novel forwarding and routing mechanism design in SDN-based NDN architecture

Combining named data networking（NDN） and software-defined networking（SDN） has been considered as an important trend and attracted a lot of attention in recent years. Although much work has been carried out on the integration of NDN and SDN, the forwarding mechanism to solve the inherent problems caused by the flooding scheme and discard of interest packets in traditional NDN is not well considered. To fill this gap, by taking advantage of SDN, we design a novel forwarding mechanism in NDN architecture with distributed controllers, where routing decisions are made globally. Then we show how the forwarding mechanism is operated for interest and data packets. In addition, we propose a novel routing algorithm considering quality of service（QoS） applied in the proposed forwarding mechanism and carried out in controllers. We take both resource consumption and network load balancing into consideration and introduce a genetic algorithm（GA） to solve the QoS constrained routing problem using global network information. Simulation results are presented to demonstrate the performance of the proposed routing scheme.