Grooming In Optical Networks Research Articles

Logical topology design for dynamic traffic grooming in WDM optical networks

Traffic grooming in optical networks refers to consolidation of subwavelength client connections onto lightpaths. Depending on whether client connections are given in advance or randomly arrive/depart, traffic grooming is classified as static and dynamic. Dynamic traffic grooming has been traditionally performed through establishing/releasing lightpaths online. In this paper, the authors propose an alternate approach to design a static logical topology a priori and then route randomly arriving client connections on it to avoid frequent lightpath setup/teardown. Two problems are considered: 1) minimize resource usage constrained by traffic blocking requirements and 2) maximize performance constrained by given resources. These are formulated as integer linear-programming (ILP) problems. The numerical results show that the resource usage dramatically decreases when the blocking requirement is relaxed, and the grooming performance slowly increases when given more resources. In addition, the number of ports at client nodes has more profound impact on traffic grooming than the number of wavelengths.

Optimization in telecommunication networks

Network design and network synthesis have been the classical optimization problems in telecommunication for a long time. In the recent past, there have been many technological developments such as digitization of information, optical networks, internet, and wireless networks. These developments have led to a series of new optimization problems. This manuscript gives an overview of the developments in solving both classical and modern telecom optimization problems. The classical (still actual) network design and synthesis problems are described with an emphasis on the latest developments on modelling and solving them. Mathematical theorems will be related to the models described. This includes menger's disjoint paths theorem, the ford–fulkerson max-flow-min-cut theorem, and also gomory–hu trees and the okamura-seymour cut-condition finally, we describe recent optimization problems such as routing, wavelength assignment, and grooming in optical networks.

Analysis of Optical Networks With Heterogeneous Grooming Architectures

Traffic grooming in optical networks employing wavelength division multiplexing (WDM) has gained prominence due to the prevailing disparity between the user requirement and wavelength capacity. Nodes in an optical network get upgraded to the latest grooming technology slowly with time. Hence, WDM grooming networks are expected to employ heterogeneous grooming architectures. In this paper, we develop an analytical model to evaluate the blocking performance of WDM grooming networks with heterogeneous grooming capabilities. We demonstrate the accuracy of the analytical model by comparing the analytical results with that of the simulation. We observe that analytical models with and without precise knowledge of the grooming architectures predict similar performance. The proposed analytical model can be employed by resource placement algorithms that identify a set of nodes and links that need to be upgraded when the resources are limited.

Dynamic Routing in WDM Grooming Networks

Traffic grooming in optical networks has gained significant importance in recent years due to the prevailing sub-wavelength traffic requirement of end-users. In this paper, a methodology for dynamic routing of fractional-wavelength traffic in WDM grooming networks is developed. To evaluate the performance of routing algorithms, a new performance metric that reflects the network utilization is also proposed. The performances of shortest-widest path, widest-shortest path, and available shortest path routing algorithms are evaluated on a class of WDM grooming networks by considering traffic of different capacity requirements. The effect of dispersity routing, where higher capacity requests are broken into multiple unit capacity requests, is also investigated. The most interesting counter-intuitive result that is observed is that increasing the grooming capability in a network could result in degrading the performance of the widest-shortest path algorithm.