Wdm Optical Transport Network Wavelength Converter Configuration And Virtual Topology Design Problem

With the rapidly expanding of information society, the requirement of promoting the capacity of broadband network has increased dramatically. Optical Transmission Network based on Wavelength-division multiplexing (WDM) technique has became a hot research field now, because of its large capacity and agility. This dissertation manly focuses on the issues of wavelength converter optimal placement, limited-range wavelength conversion and virtual topology design. Giving Mesh-torus as an example, we first address the issue of wavelength converter optimal placement in regular network. Uniform placement in a single link is a sort of optimal placement, which is reported in correlated papers. Chapter 2 applies this conclusion on the Mesh-torus. The results show that the performance of uniform placement in the Mesh-torus is not only better than other placement scheme, but close to the performance of virtual wavelength path, so it is an optimal scheme. But in the irregular network, it isn't easy to realize uniform placement on all optical paths; so heuristic algorithm is necessary to be adopted. Some algorithms have been mentioned in related papers, but these algorithms need large numeration. A new placement algorithm is proposed in Chapter 3, it can reduce the iteration number considerably. To lower the requirements of the wavelength converter performance, Limited-range wavelength conversion technique was employed in some papers. To reduce more network cost, Chapter 4 integrates Partial Virtual Wavelength Path with Limited-range wavelength conversion technique. The results show that the integrating can not only keep the previous network performance, but reduce the requirements of the wavelength converter performance and the network cost. Issue of virtual topology design is discussed in Chapter 5. In the chapter, we summarize some previous algorithms, and then use the Layered-graph mode to improve on traditional split-step design method. A changed algorithm is presented in this section, and the result shows that changed algorithm can reduce the using of wavelength resource than the previous one.