Optical networks have been widely implemented and they are usually used as the backbone of high-capacity telecommunication infrastructures. However, the nowadays traffic demand over these networks has increased in a way that congestion over the architecture is considerable. Due to the high costs of implementing new optical links, the routing and wavelength assignment process become an important...

The problem of routing and wavelength assignment (RWA) in wavelength division multiplexing (WDM) optical networks consists in routing a set of lightpaths and assigning a wavelength to each of them, such that lightpaths whose routes share a common fiber are assigned different wavelengths. This problem was shown to be NP-hard when the objective is to minimize the total number of wavelengths used....

This paper deals with the wavelength assignment problem in WDM all-optical networks. This problem can be abstracted as a multicoloring on a weighted conflict graph. The main focus of this work is to obtain the relationship between the wavelength assignment and the multicoloring problems. We, first, establish a new result regarding multicoloring problem in which we provide a tight bound for any ...

In this paper, we will discuss the wavelength requirement for optical networks based on wavelength-division multiplexing (WDM). A mathematical model, to represent the routing and wavelength assignment in optical networks with or without wavelength conversion, is described, and metrics are defined to express the performance. A new heuristic for routing and wavelength assignment is proposed and c...

Title of Document: APPLICATION OF ANT COLONY OPTIMIZATION TO THE ROUTING AND WAVELENGTH ASSIGNMENT PROBLEM Eunmi Kim, Masters of Science, August 2007 Directed By: Associate Professor, Dr. Richard J. La, Department of Electrical and Computer Engineering The transmission capacity of a link in today’s optical networks has increased significantly due to wavelength-division multiplexing (WDM) techno...

In this paper, we propose a heuristic multicast routing algorithm, which minimizes the cost while satisfying both the wavelength required and hop length selection. The algorithm consists of two subproblems: the wavelength assignment & the routing path selection. For solving the wavelength assignment subproblem, an auxiliary graph is created where by the nodes and the links in the original netwo...

Optical networks are in the evolution of transparent architectures, the effects of the physical layer impairments are becoming more and more prominent. This paper setting out from multiple physical impairments, analyzes the effects as well as the diversity and complexity of the physical layer impairments in optical networks, investigates the issue of the current-related physical layer impairmen...

We consider a NP-hard problem related to the routing and wavelength assignment (RWA) problem in optical networks, dealing with scheduled lightpath demands (SLDs) with multiplicity. A SLD is a connection demand between two nodes of the network, during a certain time. Each SLD requires a given number of wavelengths (its multiplicity). Given a set of SLDs, we want to assign a lightpath (i.e. a rou...

We present a review of column generation formulations for the Routing and Wavelength Assignment (rwa) problem with the objective of minimizing the blocking rate. Several improvements are proposed together with a comparison of the different formulations with respect to the quality of their continuous relaxation bounds and their computing solution ease.