持续性灾害下风险感知的光网络业务恢复算法

Risk-aware Optical Network Service Restoration Algorithm under Persistent Disasters

【目的】地震等自然灾害具有持续性和大范围的特性。灾害在发生过程中会持续性损伤光网络的链路资源,造成其链路风险不断变化。面对持续变化的链路风险,业务恢复规划不当可能导致恢复业务再次发生故障。从业务角度来看,重复故障将导致数据传输的多次中断,且随着灾害发生,后续的链路状态损伤加剧可能导致无法恢复此业务。从网络管控方面来看,重复恢复会造成算路资源浪费,占用其他业务的恢复资源。同时,由于业务传输的数据重要性不同,不同业务对传输可靠性的需求存在差异,在发生故障时,高重要度业务应优先恢复。因此,在大规模持续性灾害场景下,综合考虑灾害对链路风险的持续性影响以及不同业务对路径可靠性需求的差异性进行业务恢复是一个值得研究的问题。文章针对此问题提出了一种持续性灾害下基于链路风险感知的业务恢复算法——动态链路风险重路由算法(DLRRA)。【方法】首先,针对业务重要度和链路风险,文章建立了业务重要度与链路风险评估模型,并在此基础上提出了优化目标路由可靠度。DLRRA结合优化目标充分考虑了灾害对链路持续性影响造成的链路风险度变化,通过优先为高重要度的故障业务分配低风险的恢复资源,避免了在灾害持续发生过程中同一高重要度业务发生2次故障的风险。【结果】仿真结果表明,DLRRA恢复的首次业务较传统算法的2次故障概率降低了11%,且在高负载下的平均重要度提高了10%。【结论】因此,该算法有效避免了持续性故障造成的业务多次中断带来的损失,保证了重要业务在灾害环境中的持续稳定运行。

【Objective】Natural disasters such as earthquakes have the characteristics of persistence and wide range.During the occurrence of disasters,the link resources of the optical network will be continuously damaged,resulting in the constant change of the link risk.In the face of constantly changing link risks,improper service recovery planning may cause service failures.From a service perspective,repeated faults will interrupt data transmission many times,and the subsequent link status damage may be aggravated after a disaster occurs.From the perspective of network management and control,repeated recovery wastes route calculation resources and occupies the recovery resources of other services.At the same time,different services have different requirements for transmission reliability because of the importance of the data to be transmitted.When a fault occurs,the high-importance services should be recovered first.Therefore,in the scenario of a large-scale persistent disaster,it is a problem worth studying to comprehensively consider the sustained impact of the disaster on link risk and the difference in path reliability requirements of different services for service recovery.To solve this problem,this paper proposes a link risk-aware service recovery algorithm-Dynamic Link Risk Reroute Algorithm(DLRRA)under persistent disasters.【Methods】Firstly,according to the service importance and link risk,we establish the service importance evaluation model and link risk evaluation model.Then we propose the optimization target route reliability.The DLRRA,combined with the optimization objective,fully considers the change of link risk degree caused by the impact of disasters on the continuity of links.By preferentially allocating low-risk recovery resources to the fault services of high importance,the risk of secondary failure of the same high-importance services is avoided during the continuous occurrence of disasters.【Results】The simulation results show that the second failure probability of DLRRA recovery is reduced by 11%compared with the traditional algorithm,and the average importance of DLRRA recovery under the high load is increased by 10%.【Conclusion】Therefore,the algorithm effectively avoids the loss caused by multiple service interruptions caused,and ensures the continuous and stable operation of important services in the disaster environment.