tailieunhanh - Routing and Wavelength Assignment in Optical WDM Networks phần 1

Tham khảo tài liệu 'routing and wavelength assignment in optical wdm networks phần 1', kỹ thuật - công nghệ, kĩ thuật viễn thông phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Routing and Wavelength Assignment in Optical WDM Networks George N. Rouskas Department of Computer Science North Carolina State University Raleigh NC 27695-7534 Phone 919-515-3860 Fax 919-515-7925 Email rouskas@ Abstract This article discusses the routing and wavelength assignment RWA problem in optical networks employing wavelenength division multiplexing WDM technology. Two variants of the problem are studied static RWA whereby the traffic requirements are known in advance and dynamic RWA in which connection requests arrive in some random fashion. Both point-to-point and multicast traffic demands are considered. Keywords Wavelength division multiplexing WDM Optical networks Routing and wavelength assignment RWA Virtual topology design Optical multicast 1 Introduction to Optical WDM Networks A basic property of single mode optical fiber is its enormous low-loss bandwidth of several tens of Terahertz. However due to dispersive effects and limitations in optical device technology single channel transmission is limited to only a small fraction of the fiber capacity. To take full advantage of the potential of fiber the use of wavelength division multiplexing WDM technology has become the option of choice. With WDM a number of distinct wavelengths are used to implement separate channels 1 . An optical fiber can carry several channels in parallel each on a particular wavelength. The number of wavelengths that each fiber can carry simultaneously is limited by the physical characteristics of the fiber and the state of the optical technology used to combine these wavelengths onto the fiber and isolate them off the fiber. With currently available commercial technology a few tens of wavelengths can be supported within the low-loss window at 1550 nm but this number is expected to grow rapidly in the next few years. Therefore optical fiber links employing WDM technology have the potential of delivering an aggregate throughput in the order of Terabits per second .