Research On Load-balanced Adaptive Fragment Suppresssion And High Survivability Resource Allocation Algorithms In SDM-EONs

Elastic optical networks(EONs)have a fine-grained spectrum allocation granularity,and can adaptively allocate spectrum resources to business connections based on their bandwidth requirements.Therefore,it is considered as an effective solution to the continuous increase of backbone network traffic.Due to the slow growth of the fiber channel capacity limited by the nonlinear Shannon limit of single-mode fibers,space-division multiplexing technique supported by multi-core fibers(MCF)or multi-mode fibers(MMF)is introduced as a new transmission technology in the research of EONs to cope with the explosive growth of bandwidth applications such as cloud services.Space-division multiplexing elastic optical networks(SDM-EONs)extend the problem of network resource allocation to the spatial dimension.The increase of allocation complexity and the intensified generation of spectrum fragments pose new challenges for the research of network resource allocation.Specifically,the resource allocation of SDM-EONs based on MCF has received the most attention,terme routing,spectrum and core assignment(RSCA).In addition,the increase of network traffic carried by SDM-EONs also puts forward higher requirements for the survivability of the network.Therefore,the research content of this paper is load-balanced adaptive fragment suppression and high survivability resource allocation algorithms in SDM-EONs.The main research work of the paper is as follows:(1)Aiming at the problem of load unevenness in the routing allocation of SDM-EONs,an optimized load-balanced adaptive routing allocation(OLARA)algorithm is proposed.The algorithm consists of a genetic algorithm-assisted offline weight modification(GAAOWM)algorithm and a resource utilization aware weight adjustment(RUAWA)algorithm after the request arrives.The OLARA algorithm considers the factors such as the physical transmission cost,the morphological structure of the network topology,the distribution of services and the real-time utilization of network resources in the optimal routing selection.Simulation results show that the GAAOWM algorithm has good topology universality.Compared with the traditional routing algorithm,the offline adjustment caused by GAAOWM algorithm improves the load balancing degree of small,medium and large topologies by about 20%to 67%.The optimization effect on the sparse-link network topology is particularly obvious,and its average improvement is higher than 40%.The RUAWA algorithm is the complement to GAAOWM algorithm.It uses a low-complexity link weight update strategy to effectively implement load balancing adjustments that are synchronized with resource allocation.It plays a significant role in optimizing the network blocking probability.(2)Aiming at the problem of spectrum fragments generation in the resource allocation of SDM-EONs,a flexible grouping mechanism is proposed.A new RSCA algorithm for SDM-EONs based on MCF called weight updating flexible grouping routing spectrum and core assignment(WUFG-RSCA)algorithm based on mixed super-channel is proposed with the consideration of the load-balanced adaptive routing algorithm.The flexible grouping mechanism guarantees the continuity of idle spectrum resources by request aggregation,spectrum resource grouping and quantity relationship limitation,thereby suppressing the generation of spectrum fragments.The WUFG-RSCA algorithm realizes the aggregation and reuse of spectrum fragments through the adoption of mixed super-channel.Also,the WUFG-RSCA algorithm reduces the complexity of resource allocation caused by searching and constructing mixed super-channel by limiting the allocation range of mixed super-channel.Compared with the traditional ungrouped RSCA algorithm,the simulation results based on the classic topologies show that the WUFG-RSCA algorithm can achieve more than 80%suppression of spectrum fragments,around 70%decrease of network transmission blocking probability and more than 30%improvement of spectrum resource utilization.Compared with variable and hybrid grouping RSCA algorithms,WUFG-RSCA algorithm can achieve at least 70%spectrum fragmentation suppression,35%reduction in transmission blocking probability and 5%improvement in spectrum resource utilization.In addition,WUFG-RSCA algorithm introduces a priority differentiation mechanism.Ensuring the quality of service of low priority requests,WUFG-RSCA algorithm guarantees that the mean blocking probability and time delay of requests with high priority are about 28%and 35%of their counterparts with low priority,respectively.(3)To guarantee the survivability of SDM-EONs,a crosstalk-aware dedicated protection(CaDP)algorithm and a topology-adaptive shared backup path protection(TA-SBPP)algorithm are proposed based on the traditional technology of dedicated and shared backup path protection.The CaDP algorithm achieves crosstalk avoidance through the setting of backup priority allocation core and the combination of multiple allocation strategies.Simulation results show that the CaDP algorithm can achieve at least 16%crosstalk optimization and 10%transmission blocking probability suppression compared to the crosstalk-unaware RSCA algorithm.The TA-SBPP algorithm adopts the idea of priority sharing.It fully considers the impact of topology size and crosstalk in MCF when adjusting the link weights to realize priority sharing.Thus,TA-SBPP algorithm has good topology universality.Compared with the original priority sharing algorithm,TA-SBPP algorithm achieves at least 19%protection overhead suppression,23%crosstalk suppression and 7%transmission blocking probability reduction while ensuring the topology applicability.