Detecting and recovering failure in time is a very important criteria for evaluating the practical value of network. For shortening the time of service disruption and enforcing the reliability of network,it is necessary to study the failure detection and recovery techniques in the SDN network. By analyzing the features of the existing two SDN failure recovery mechanisms and their limitations,a synthesized failure recovery approach combined with proactive recovery and reactive recovery schemes,including that considers the quality of service of packet flow,is proposed. A system based on open source OpenDaylight controller is designed and implemented,which uses asyn-chronous alert to detect network failures,and diagnoses failures depending on the number of failures and the service properties of flows af-fected by the failures. Three recovery modes,includes proactive,deliberative,reactive modes,are proposed to recovery automatically ac-cording to the diagnostic results. Test results show that the scheme can automatically choose proper recovery mode based on failure type, and the recovery effect is good.%及时检测和恢复故障是评价网络实用价值的一个十分重要的指标.为了缩短服务中断时间,增强网络可靠性,有必要研究SDN(软件定义联网)网络中的故障检测和恢复技术.基于对现有SDN网络中的两种故障恢复机制的特点及其限制的分析,提出了一种主动式和被动式故障恢复相结合的、综合考虑分组流服务质量需求的故障恢复方案.基于开源OpenDaylight控制器设计和实现了一个系统,采用异步告警和主动轮询方式检测网络故障,根据故障数目和受故障影响的流的业务属性对故障进行诊断,设置三种故障恢复模式:主动式、审议式和被动式.自动根据诊断结果对故障进行恢复.测试结果表明,该方案能自动地根据故障类型选用合适的恢复模式,并且恢复效果良好.
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