Study Of Routing And Spectrum Assignment Algorithm Based On Multi-Parameter Constraints In Flexible Optical Networks

With the rapid development of novel network services, such as the cloud service and bid data, the Internet traffic is booming in a high rate. However, the traditional wavelength division multiplexing(WDM) optical networks adopt the fixed channel spacing, leading to inefficient spectrum resource allocation. In order to make full use of the bandwidth resource, the flexible gird technology is introduced. It employs finer grained frequency gap spacing and allocates the matched spectrum resources for the requests according to the bandwidth requirement, implementing the elastic bandwidth allocation. At the same time, the bandwidth resource utilization rate is improved. Meanwhile, because of the diversity and complexity of the network services, they are required to be customized. In view of this, the control and management of the optical networks tend to be software-defined, more flexible, and intelligent.However, the physical impairments are still to be the major factor for the establishment of the end-to-end connection in the development of the optical networks. In addition, the energy consumption problem has become increasingly prominent with the increasing service volume. In this context, the routing and spectrum assignment(RSA) scheme with the constraints of physical impairments and energy consumption is mainly researched in flexible optical networks to effectively guarantee the connection establishment and improve the network performance. The main research achievements are as following:(1) This paper has proposed a modulation format adaptive RSA algorithm in flexible optical networks. The transmission distance is modeling with the physical impairments fully considered. The modulation formats are selected adaptively to take the routing and spectrum resource allocation process based on the different distances between two nodes. The proposed algorithm can meet the quality of transmission(Qo T) requirement, lower the network blocking probability, and also improve the network resource utilization.(2) Based on the weight analysis, the link cost function is defined considering the physical impairments and energy consumption simultaneously. For different grade traffic, the best weight coefficients are set. Then, this paper has developed a Qo T-energy assessment model and also a novel weighted energy efficient RSA scheme. The routing process is taken for different requirements of the various services, greatly reducing the overall energy consumption with the guarantee for quality of service(Qo S). This scheme can make a better balance between the Qo S and energy efficiency.(3) This paper has designed an impairment-energy aware control plane considering the effect of physical impairments and the energy-saving requirement in software-defined flexible optical networks. This control plane has been expanded to the multi-domain network environment. Considering the diversification of network services, a corresponding control mechanism and also a multi-domain RSA scheme for service differentiation are proposed. The simulation results indicate that our scheme can lower the network blocking probability and achieve the energy efficiency. The spectrum resource utilization is also improved with the acceptable set up delay.