QoS约束的链路故障多备份路径恢复算法

链路故障的恢复，不仅仅是选择一条连通的备份路径问题，还应考虑网络业务故障恢复过程中的QoS需求。针对此问题，该文基于多备份路径策略，构建概率关联故障模型和重路由流量丢弃量优化目标。并基于该优化目标，以业务的QoS需求为约束，建立故障恢复问题的数学模型，提出一种QoS约束的链路故障多备份路径恢复算法。该算法构建单条备份路径时，以最大程度地减少重路由流量丢弃为目标，并采用改进的QoS约束的k最短路径法进行拼接，且给与高优先级链路更多的保护资源。此外还证明了算法的正确性并分析了时间空间复杂度。在NS2环境下的仿真结果表明，该算法显著提升了链路故障恢复率和重路由流量QoS满足率，且QoS约束条件越强，相较于其它算法优势越明显。

Link Failure Recovery Algorithm Based on Multiple Backup Paths with QoS Constraint

Recovery of link failure is not only the issue of selecting a connected backup path, but the QoS requirement in the process of failure recovery of the network service should be also taken into account. The probabilistically correlated failure model and rerouting traffic disruption optimization target are built based on multiple backup paths strategy. Furthermore, a mathematical model of the failure recovery problem is modeled, which takes the minimum rerouting traffic disruption as the target and the QoS requirement as the constrain, and a link failure recovery algorithm based on multiple backup paths with QoS constrain is proposed. The proposed algorithm takes reducing rerouting traffic disruption farthest as the target and adopts the improved k shortest path algorithm with QoS constrain to splice the single backup path, and it gives the links more protection resource with high priority. Moreover, the correctness of the proposed algorithm is proved, and the time complex and the space complex are computed. The simulation results under NS2 show that the proposed algorithm significantly improves link failure recovery rate and the QoS satisfaction rate of the rerouting traffic, and it performs better when the QoS constrain is stronger.