An Analytical Framework for the Performance Evaluation of Node- and Network-Wise Operation Scenarios in Elastic Optical Networks

In this paper, we analyze the exact node- and network-wise operation scenarios in elastic optical networks (EONs). First, the busy/idle patterns of optical spectrum in a stand-alone node are modeled by utilizing a continuous Markov chain. In the node-wise perspective, four operation scenarios are investigated, which are determined based on the spectrum allocation methods. We present an algorithmic procedure to derive the global balance equations of the corresponding Markov chains for all operation scenarios. Furthermore, the network-wise operation is assessed by analyzing the end-to-end blocking probability for two operation modes, with and without spectrum conversion capabilities at the intermediate nodes. Because the computational complexity of exact model increases exponentially versus the number of spectrum slots, we present two approximate alternatives. The results of the exact models, approximations, and verifying simulations are compared for small scale problem. Comparison reveals that the exact model and simulation match very well. In addition, the accuracy of both approximations is acceptable. The approximate solutions are also examined under large scale scenarios by considering simulation results as a benchmark. The accuracy of the first approximation is not degraded in large scale cases, as opposed to the second one, which is only applicable to small scale problems.