Multi-dimensional Dynamic Routing And Spectrum Allocation Algorithms In Software Defined Elastic Optical Networks

Due to the emerging of new network applications,the traffic bandwidth require-ments are diversified.In order to improve the spectrum efficiency,Elastic Optical Net-works(EON)with flex-grid was proposed.The spectrum can be divided into fine gran-ularity in EON,which makes the issue of Routing and Spectrum Allocation(RSA)more difficult.Therefore,it is urgent for EON to combine with an intelligent management platform.Software Defined Network(SDN)is well known as a centralized control ar-chitecture.And the combination of SDN and EON leads to Software Defined Elastic Optical Networks(SD-EON).By taking advantage of the SDN centralized control ar-chitecture,SD-EON provides an easier way to acquire the information of the network resources,thus provides a better solution to the RSA problem.In this paper,we first introduce the background of the SD-EON and analyze the research status of EON,SDN and SD-EON,respectively.We also illustrate the network architecture of the SD-EON,compare several SDN controllers,introduce the optical equipment of the SD-EON platform and some commands of Mininet,and present an extended OpenFlow Protocol for SD-EON.And then,we investigate the spectrum fragmentation issue of EON,summarize and analyze some existing RSA algorithms in EON and SD-EON.In addition,we propose a Hop and Consecutiveness based Routing and 2D Frag-mentation-aware Spectrum Assignment algorithm(HCR-2D-FSA)for SD-EON archi-tecture with a joint consideration of hop and spectrum consecutiveness in routing selec-tion and both horizontal and vertical fragmentations during spectrum assignment.Due to the consideration of two dimensional network resources,HCR-2D-FSA achieves better blocking probability and fragment degree compared with the previous works.Morover,we propose a 3D Fragmentation-Aware Routing and Spectrum Assign-ment algorithm(3D-FA-RSA).Our algorithm first analyzes the SD-EON network re-sources in three dimensions,i.e.,spectral,spatial and temporal domain,and designs a three-dimensional resource model.To describe the three-dimensional resource model,we introduce some novel notations,such as two-dimensional pruning,link code,weight of run,three-dimensional similarity and three-dimensional segmentation.Both immediate reservation(IR)request and advance reservation(AR)request are considered in our 3D-FA-RSA algorithm,where lightpaths are established for the IR requests as soon as the arrival of the requests;on the other hand,initial delay of data transmission is tolerated for the AR requests,as long as the resources are allocated before the deadline of the AR requests.The three dimensional fragmentation is also reduced in the proposed algorithm,which can improve the blocking probability,fragmentation probability,resource simi-larity,resources consecutiveness and resources utilization.Finally,we set up a NSFNET topology in the Mininet,and simulate the SD-EON network traffic model by design a custom iperf command.We implement our two novel algorithms in RYU controller,and make a comparison with related algorithms,and the simulation results verify the effectiveness of our proposed algorithms.