Routing And Spectrum Assignment Based On Ant Colony Algorithm In Flexible Optical Networks

With the development of optical network and better quality required by users, optical network has to be developed with larger capacity and lower power consume, so the flexible bandwidth optical network has been proposed, which is auto-adaptive when assigning resources according to the utilization rate of resource in the current network. It draws more and more attention due to its higher utilization ratio of spectrum resource. This paper researches the routing and spectrum assignment strategy based on the flexible bandwidth optical network.Similar to WDM networks, the most important issue is to solve the Routing and Wavelength Assignment (RWA) strategy, in flexible optical networks, the problem is to solve the Routing and Spectrum Assignment (RSA) strategy. In this paper, an adaptive RSA strategy based on the ant colony algorithm is proposed. The result of simulation show that the proposed strategy diminishes the blocking probability of the network.Different from traditional WDM networks, whose minimum unit of resource distribution is wavelength, the assignment unit of flexible bandwidth optical network is consecutive spectrum. According to the situation, the concept of "continuation if spectrum" is introduced to resolve the spectrum assignment in flexible bandwidth optical network, It allows people to assign appropriate spectrum resource based on different service requests, which lead to higher utilization ratio of limited spectrum resource.In order to improve the performance of RSA based on ant colony algorithm, ant-based alternate routing algorithm is presented to further diminish the blocking probability of the network and raise the utilization rate of spectrum resource.The RSA based on ant colony algorithm is expounded explicitly in this paper, simulation on platform of OMNet++shows that the RSA strategy proposed in this paper improves the performance of the network.