With standard assumptions the routing and wavelength assignment problem (RWA) can be viewed as a Markov Decision Process (MDP). The problem, however, defies an exact solution because of the huge size of the state space. Only heuristic algorithms have been presented up till now. In this paper we propose an approach where, starting from a given heuristic algorithm, one obtains a better algorithm by the first policy iteration. In order to estimate the relative costs of states, we make a simulation on the fly studying, at each decision epoch, the consequences of all the alternatives actions.

With wavelength division multiplexing (WDM) several optical signals can be transferred in a single optical fiber [6] [7]. This technology allows more efficient use of the huge capacity of an optical fiber but also poses new network design and management problems, especially when wavelength conversion is not possible in the nodes. In this paper we consider the routing and wavelength assignment problem in such networks. Once routes are fixed the wavelength assignment is essentially a graph coloring problem. Several heuristic methods for coloring a given graph are studied. Also an iterative algorithm for finding a reasonably good routing and wavelength assignment is represented and tested with fully connected networks.

...................................................................................................................................... viii List of publications .......................................................................................................................ix Chapter 1: Introduction..................................................................................................................1 1.1 Scope and overall research contribution..............................................................................1 1.2 Motivation............................................................................................................................2 1.2.1 The interconnect problem .............................................................................................2 1.2.2 Capabilities and limitations of electrical interconnects................................................4 1.2.3 Advantages of optical interconnects ......................................

With wavelength division multiplexing #WDM# several optical signals can be transferred in a single optical #ber #6##7#. This technology allows more e#cient use of the huge capacity of an optical #ber but also poses new network design and management problems, especially when wavelength conversion is not possible in the nodes. In this paper we consider the routing and wavelength assignment problem in such networks. In a single #bre case the the wavelength assignment is essentially a graph coloring problem once the routes are #xed. With multiple-#bres the problem changes a little and can no longer be presented as graph node coloring. Chosen routing has great impact to the #nal solution and an iterative algorithm for choosing the routes is brie#y studied. 1 Introduction The ever increasing demand of higher transmission bandwidth requires new solutions. One promising concept for increasing the capacity is wavelength division multiplexing #WDM#. In WDM several optical signals usin...

We describe the first iteration of a comprehensive model with which we can investigate the practical limits on optical bus bandwidth and number of bus processing modules for given signal power. The selection algorithm will ultimately allow programmable evaluation of system parameters bus bandwidth, optical power budget, electrical power budget, number of modules and space consumption for an optimal design that is suited to on-the-fly system reconfiguration.

With wavelength division multiplexing (WDM) several optical signals can be transferred in a single optical fiber [6][7]. This technology allows more efficient use of the huge capacity of an optical fiber but also poses new network design and management problems, especially when wavelength conversion is not possible in the nodes. In this paper we consider the routing and wavelength assignment problem in such networks. In a single fibre case the the wavelength assignment is essentially a graph coloring problem once the routes are fixed. With multiple-fibres the problem changes a little and can no longer be presented as graph node coloring. Chosen routing has great impact to the final solution and an iterative algorithm for choosing the routes is briefly studied.