Risk-aware Optical Network Service Restoration Algorithm under Persistent Disasters

Abstract

【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.

Keywords

• optical networks;optical fiber damage;link risk;fault recovery algorithm