A Study Of Distance Adaptive Routing And Spectrum Allocation In Flexible Optical Networks

Currently, with the population of broadband service as well as the advent of new bandwidth-intensive services, the network bandwidth demand is booming in a high rate, which comes up with the higher requirements for transmission capacity and resource demands. However,the traditional WDM network must adopt to the fixed ITU-T spectrum division mechanism, which cannot flexibly meet business requiements, and lead to the serious waste of network resources.The flexible optical networks support finer granularity segmentation and dynamic regulation of optical spectrums, finer spectrum resources are segmented and appropriate numbers of frequency slots are allocated to each service according to its bandwidth requirement, improving the utilization efficiency of network bandwidth resources.In this paper, we study the problems of routing and spectrum allocation(RSA) in flexible optial networks. Firstly, according to the analysis of distance-adaptive modulation and service-split technique, we propose a service-split and distance-adaptive spectrum allocation algorithm. OMNeT++ network simulation tools are used to establish the simulation platform of flexible optical networks. Simulation results show that the algorithm can significantly improve performance of the network blocking probability and save the bandwidth resource. Secondly, we study the fairness issue of different bandwidth services in flexible optical networks. On the basis of previous research, a service-split technique is introducd into spectrum allocation, and the Service-Split Rough-Partition approach is presented and simulated. Simulation results demonstrate that the proposed method achieves higher fairness index and better blocking performance.