Research Of Routing And Spectrum Allocation Stratergies And Algorithms Of Bandwidth Variable Elastic Optical Networks

Since the beginning of commercial fiber-optic communications, multimedia services have developed rapidly, and lead to a fast growth in network bandwidth demands. However, the amount of spectrum resources are limited, which prompting us to abandon the extensive use of network resources and constantly seeking for high spectral efficiency solutions.The current WDM network adopt the fixed50GHz ITU-T spectrum division mechanism which considered with a low spectrum efficiency, In this context, the researchers proposed bandwidth variable elastic optical networks based on OFDM technology which are regarded as spectrum efficient network architectures. OFDM technology is a multi-carrier transmission technique dividing a high-speed data stream into a plurality of parallel low-speed data for transmission. Elastic optical networks are also called ultra dense wavelength division multiplexing(UDWDM) networks.The research focuses of elastic optical networks mainly include the network architecture, the design of key nodes as well as the strategies and algorithms adopt in the networks. This paper focuses on the study of elastic optical network routing and spectrum resource allocation mechanisms and algorithms. The main work of this paper are summarized as follows:(1) OOFDM-based flexible optical network Overview:After detailed reading and analyzed a large number of elastic optical network related works, the paper presented a full introduction of elastic optical networks, including the concept, the main characters, the key hardware design and the current main network strategies and algorithms.(2)Proposed the Adaptive Sub-carrier Distribution Routing and Spectrum Allocation Algorithm:the concept of adaptive subcarrier distributed allocation is introduced to elastic optical networks. Unlike the centralized allocation, the adaptive subcarrier distributed allocation allows one node pair establishes more than one lightpaths and the connection needs can only be partially met. After conducting adequate simulations in static layer as well as dynamic layer, the comparative analysis of ASD-RSA algorithm with other algorithms has proved that the ASD-RSA algorithm reduces network congestion rate largely, therefore improve the spectral efficiency of the networks.