一种拥塞避免的SDN单链路故障恢复模型

Failure Recovery Model for Single Link with Congestion-Avoidance in SDN

软件定义网络(Software Defined Network,SDN)作为一种新型网络架构,通过分离数据平面与控制平面来简化网络管理逻辑,是下一代网络的研究热点。但是,由于频繁的链路故障等因素,SDN网络的可靠性成为公认的业界难题。当前已有的SDN链路故障恢复模型存在恢复时延过长、消耗过多流表项、忽视故障恢复后链路拥塞的问题。为了解决这些问题,提出了一种基于段路由(Segment Routing,SR)的单链路故障恢复模型(Loop Free Alternates-Congestion Aware,LFA-CA)。该模型包含了两个启发式算法BPF和BPU,分别用于在网络初始化时计算无环的备份路径,和在运行过程中更新拥塞避免的备份路径,实现了针对单链路故障的快速恢复和故障恢复后的拥塞避免。大量仿真实验证明了LFA-CA相比当前的SDN单链路故障恢复模型消耗了更少的转发规则,且具有更好的故障后负载均衡能力。

As a new network architecture,the software defined network(SDN)simplifies the network management logic by separating data plane and control plane,which is one of the popular research subjects of next-generation network.However,due to frequent link failures and other factors,it is difficult to guarantee the reliability of SDN,which is a problem well recognized in the industry.The existing SDN link failure recovery models often have the problems of long recovery delay,requiring too many flow entries and ignoring link congestion after recovery from failure.To solve these problems,this paper proposes a single-link failure recovery model(LFA-CA)based on segment routing(SR).The model employs the two heuristic algorithms of BPF and BPU to calculate a loop-free backup path during network initialization and update the congestion avoiding backup path during operation,respectively,so as to achieve fast recovery from single-link failure and congestion avoidance after failure.In this paper,massive simulation experiments are carried out to evaluate the performance of our model,and the results prove that compared with some of the existing SDN single-link failure recovery models,LFA-CA consumes less forwarding rules and has better load balancing ability after failure.