Technical Research Of Routing And Spectrum Allocation In Elastic Optical Networks

With the rapidly development of broadband service and cloud computing and Internet of things,the Internet traffic has been undergoing exponential growth,which has challenged a lot to the existing optical network.Conventional wavelength-division-Multiplexing systems suffer from the drawbacks of low bandwidth utilization and short of flexibility due to its coarse granularity and rigid wavelength assignment.Large capacity,high flexibility and extensibility has become the development direction of the future communication network.The SLICE optical network can provide efficient as well as flexible spectrum assignment by providing fine granularity.But the new technology also brings challenges in routing and spectrum allocation.The research work in this dissertation is supported by the national 863 project named "the search of gridless optical switches technology and prototype with variable rate",and mainly focus on the problem of Routing and Spectrum Assignment(RSA)which can be divided into two sub problems:the routing sub problem and the spectrum assignment sub problem,and we also proposed optimization algorithms for the two sub problems respectively.The paper's main work and innovation points are summarized as follows:(1)We summed up and analyzed the five technical characteristics and the routing and spectrum allocation(RSA)problem in elastic optical networks.And then expounds the characteristics and research status of various and typical routing and spectrum allocation algorithm.(2)For routing sub problem,we defined the concept of resource centralization which can describe the resource occupation condition,and then proposed a dynamic routing algorithm,which considers the hop of the path,the resource centralization of the path as well as the entire network resource utilization.Comparing with the conventional routing algorithm,it is concluded that the algorithm can effectively reduce the blocking probability and optimize the network performance.(3)Pointing at the spectrum allocation problem,we put forward two dynamic spectrum allocation algorithms based on the maximum path resource centralization(MPRC)and maximum link resource centralization(MLRC).The simulation results show that the MPRC and MLRC can effectively gather the spectrum resource in the network,reduce spectrum fragments,make the entire network resources more concentrated,so as to reduce the blocking probability and improve the performance of the network.