为了适应互联网流量地爆炸式增长，作为底层承载管道的光网络亟需更大的网络

In order to adapt to the explosive growth of Internet traffic, the optical network as the underlying bearer pipeline urgently needs greater network capacity, smarter and more efficient management and control mechanisms. Software-defined network (Software Defined Network, SDN) decouples the control plane of the network equipment from the data plane to centrally manage and control the network, greatly simplifying network control. The Elastic Optical Network (EON) allocates resources to services on demand and uses spectrum efficiently and efficiently. It is a promising next-generation optical network. The combination of the advantages of SDN and EON forms a simple, efficient, and intelligent software-defined elastic optical network (SD-EON). However, in SD-EON, there is a problem that too much spectrum fragmentation causes a large number of requests to be blocked. In order to reduce spectrum fragmentation and reduce blocking rate, this paper introduces a path-based fragmentation metric to better assess the degree of fragmentation of spectrum resources in SD-EON. Routing and Spectrum Allocation (RSA) algorithm, which attempts to minimize the value of the fragmentation metric. Compared with three related algorithms through simulation, the algorithm in this paper can achieve better results than other algorithms in terms of the three indexes of request blocking rate, fragmentation degree and spectrum efficiency.

In order to adapt to the explosive growth of Internet traffic, optical network, as the underlying carrier pipeline, urgently needs a larger network capacity, more intelligent and efficient control mechanism. Software Defined Network (SDN) decouples the control plane of the network device and the data plane, and concentrates the control of the network, which greatly simplifies the network control. Elastic Optical Network (EON) allocates resources to the business on demand, and is a promising next-generation optical network for the flexible and efficient use of spectrum. The combination of SDN and EON creates a simple, efficient, and intelligent software-defined elastic optical network (Software-defined Elastic Optical Network, SD-EON). However, there is a problem in SD-EON where too much spectral fragmentation causes a large number of requests to be blocked. In order to reduce spectral fragmentation and reduce blocking rate, this paper introduces a path-based fragmentation metric to better evaluate the fragmentation of spectrum resources in SD-EON, and on this basis discusses an heuristic routing and spectrum allocation (Routing and Spectrum Allocation,) algorithm that attempts to minimize the value of fragmentation metrics. By comparing the simulation with the three related algorithms, the algorithm can achieve better results than the other algorithms in terms of the three indicators of request blocking rate, fragmentation degree and spectral efficiency.

In order to adapt to the explosive growth of Internet traffic, the optical network as the bottom bearing pipeline needs more network capacity, more intelligent and efficient control mechanism. Software defined network (SDN) decouples the control plane of network equipment and data plane, and controls the network centrally, which greatly simplifies the network control. Elastic optical network (eon) is a promising next generation optical network, which allocates resources to services on demand and uses spectrum flexibly and efficiently. Combining the advantages of SDN and eon, a simple, efficient and intelligent software defined elastic optical network (sd-eon) is formed. However, in sd-eon, there is a problem that a large number of requests are blocked due to too much spectrum fragmentation. In order to reduce spectrum fragmentation and block rate, this paper introduces a path based fragment measure to better evaluate the degree of fragmentation of spectrum resources in sd-eon. On this basis, a heuristic routing and spectrum allocation (RSA) algorithm is discussed, which tries to minimize the value of fragment measure. By comparing the simulation results with the three related algorithms, the algorithm in this paper can achieve better results than other algorithms in terms of three indicators: request blocking rate, fragmentation degree and spectrum efficiency.<br>