Research On Resource Allocation Method Of Communication Network Based On Elastic Optical Network

Elastic Optical Network(EON)supports more fine-grained and variable bandwidth spectrum adjustment methods and flexible carrier adjustment strategies,which can better respond to complex and changeable network service requirements and improve spectrum resource utilization.The core issue of EON is routing and spectrum assignment(Routing and Spectrum Assignment,RSA).How to establish a working optical path between the source node and the destination node according to the bandwidth requested by the service,and allocate continuous spectrum resources,has become a concern.At the same time,in a dynamic service environment,the establishment and teardown of service connections may occur at any time,and the subsequent redistribution of spectrum resources will cause spectrum fragmentation,leading to increased service congestion ratio and decreased resource utilization ratio.Therefore,considering RSA algorithm and spectrum defragmentation strategy has become a hotspot.Aiming at the problem of EON degrading network transmission performance due to unscientific and unreasonable resource allocation,we study how to reduce the network traffic congestion ratio and improve the transmission efficiency of EON in a dynamic service environment.The specific work is as follows:In view of the ubiquitous phenomenon of traditional RSA algorithm that only considers the resource allocation efficiency in the spectrum allocation scenario and ignores the relationship between routing and spectrum allocation,we propose an improved elastic optical network resource allocation algorithm based on graph coloring theory(GT-RSA)algorithm.In the route selection scenario,the GT-RSA algorithm uses the k-shortest pathes algorithm(KSP)to determine the sets of the candidate routes and constructs a relationship graph based on them.On this basis,combined with the mixed integer linear programming model of graph coloring theory,the optimal solution is obtained according to the branch and bound DSATUR(BABD)algorithm,and the coloring partition allocation of the spectrum is completed at the same time.Finally,the partition first-1 ast-fit(PAR-FLF)algorithm is used to allocate spectrum resources for services.In this paper,we use the matlab to build the EON simulation platform,and at the same time use CPLEX SOLVER to solve the mixed integer linear programming model,analyze the proposed GT-RSA algorithm in a dynamic service environment.Compared with the traditional RSA algorithm,the GT-RSA algorithm has lower spectral resource consumption,blocking ratio and higher average link continuity ratio.In view of the existing spectrum defragmentation strategies in EON,which often fail to avoid the generation of additional spectrum fragments,or when the idle spectrum resources do not match the service bandwidth requirements,the defragmentation cannot be completed.The CM-SD algorithm proposed in this paper constructs an odd-even spectrum sharing model,The idle FS can be shared and used at the connection of the odd-even spectrum area,which increases the success ratio of service connection establishment.In the process of spectrum defragmentation,a calculation model for the degree of spectrum fragmentation is constructed.Under the premise that the number of idle FS of each link is the same,the degree of spectrum fragmentation of different links can be distinguished according to the location of different spectrum fragments,and the degree of spectrum fragmentation of different links can be distinguished from the capacity matching.On the other hand,defragmenting an appropriate number of the spectrum resources for new services that are congested not only ensures the successful transmission of services,but also avoids the generation of additional fragments and reduces the ratio of spectrum fragmentation.When the idle FS in the spectrum cannot exactly match the bandwidth requirement of the service,the algorithm defragmenting all the idle FS in the spectrum into continuous spectrum blocks,which improves the continuity ratio of links and reduces the blocking ratio.