Research On Status-Aware IP+Optical Network Failure Restoration

Faced with the massive differentiated traffic brought by emerging Internet applications,network operators lease the sliced virtualized network to customers to provide specialized services.When the core IP node in the slice network fails,the traditional recovery method cannot meet user needs in terms of recovery speed and effect.The IP+optical network has the characteristics of coordinated management and control of the IP network and optical network,relazing the jointly failure recovery by IP recovery resource and optical recovery.Thus,IP layer and the flexible optical layer can jointly undertake the work of IP failure recovery.Based on network status-aware by Software Defined Network(SDN),this paper proposes a dual migration recovery method based on IP configuration migration and optical link migration to improve network reliability.The research includes the following aspects:(1)A status-aware single recovery node IP+optical dual migration recovery method is proposed.Aiming at the failure recovery of core IP node,a single recovery node IP+optical dual migration recovery mechanism is proposed.When a failure occurs,the backup recovery node and optical links in the network are searched for dual migration recovery,so that the recovery node can replace the failed node to work.Establish a single recovery node IP+optical dual migration recovery model is established and SRN-DMR algorithm is designed to realize the fast solution of the model.The simulation results show that the SRN-DMR algorithm has good search efficiency and calculation speed.In the experimental network,50%of the restoration resources are traversed to obtain recovery node,and the calculation time is only 44%of the link restoration rerouting.(2)A status-aware multiple recovery nodes IP+optical dual migration recovery method is proposed.In view of the limitation of single-recovery node IP+optical dual migration recovery,multiple recovery nodes are combined through optical layer connection to form a recovery network,which replaces the original faulty node to achieve failure recovery,and improves the applicability of dual migration recovery.Specifically,by analyzing the defects of single recovery node IP+optical dual-migration recovery,this paper designs the multiple recovery nodes IP+optical dual-migration recovery model and MRN-DMR algorithm to solve the model.In the algorithm,the innovative use of optical link extension is implemented as the status transition action in Q learning to improve the accuracy of the algorithm;the exploration area is from small to large,so that the calculation is performed in stages to improve the efficiency of the algorithm.The simulation results show that the MRN-DMR algorithm has good convergence performance and exploration and correction capabilities to avoid being trapped in local optimal solutions.When faced with the failure of the core IP node that carries a large number of services,comparing link rerouting and path rerouting,the MRN-DMR algorithm has a great advantage in computing speed.(3)A status-aware IP+optical failure recovery experimental platform is established,on which the dual migration recovery methods are tested to verify the effect of dual migration recovery.In the experimental platform,the OpenFlow-based Software Defined Network(SDN)controller searches for recovery resources based on the perceived fault information and performs recovery calculation.Dual-migration operations is profromed in the transmission plane composed by SDN switches and optical cross connect(Optical Cross Connect,OXC)equipment:the OpenFlow switching configuration of the faulty device is loaded to the recovery device,and the optical links connected to the faulty device is transferred to the recovery device,so that the recovery device replaces the faulty device in routing and connection functions.IP+optical dual migration is tested in the experimental platform.In the experimental network,compared with link restoration and rerouting,single recovery node IP+optical dual migration restoration can save 88%of the restoration time,and multiple recovery nodes IP+optical dual migration restoration can save 64%of the restoration time.Compared with traditional recovery,IP+optical dual migration recovery significantly reduces failure recovery time.