This thesis describes the concepts and technologies, as well as the performance of elastic optical networks.Fixed division of spectrum, which we encounter in traditional optical networks, will not be good enough in the near future to meet the exponential growth in traffic. It's becoming increasingly apparent that the spectral efficiency of the network is a very important factor, from both technological and economic perspective. Network elements, that will be used in elastic optical networks, will have to be capable to adapte to the network needs and help it to optimize. For this reason, the industry strives to improve the efficiency and effectivness of optical networks, using new technologies that enable better routing of signals and make better use of the available spectrum resources.
First the thesis covers the history and development, that led to the use of optical networks. Then we describe the concepts and technologies, that are used in these networks, and their limitations. In the thesis we also describe optimization problem and the process of solving it, and lastly we describe the problem of elastic network optimization as a MILP problem.