Increased competition in the telecommunications industry pushes network operators to rationalize their total costs. Models and simulations appear as major tools aiming at better understanding the expenditures and to allow a more realistic network planning. However, their focus was, in the past, mostly limited to infrastructure investments. Because emerging services pose special requirements towards the networks, operators have not only to extend the capacity of their transport networks, but also need to optimize the architecture for differentiated services with advanced packet switching technologies, referred to as Next Generation Networks (NGN). During network evolution with disruptive technology changes, a general problem faced by network operators is the service migration of active services from an existing platform into a newly setup platform. This work investigates strategies for service migration at minimized overall operational costs. A novel service migration cost model based on queueing theory and hill climbing optimization is provided in order to tackle the employee allocation optimization problem. Based on this framework, a thorough techno-economic analysis of costs and benefits is presented.

Optical systems and technologies have been radically changing the telecommunication networks for past 15 years; today wavelength division multiplexing (WDM) technology, optical amplifiers, and simple optical switching elements like optical add-drop multiplexers (OADMs) are used in the backbone networks of all operators worldwide. Optical systems nowadays provide the basis for cost-effective transmission of large amounts of bandwidth over the Internet, and will enable its future growth and the spreading of new applications and services. This paper summarizes the main trends in optical networking and investigates potential future application areas. Optical system technology has become so pervasive in network design that it needs to be considered in the context of provisioning new applications and services. Therefore, the analysis is not limited to the aspects of physical transmission, but also takes into account recent developments in integrated network design as well as network control and management. The following sections describe the key functionalities of future optical network architectures, and the key findings of the theoretical analysis are supported by the results of a field trial of advanced transmission technology

The European research project MOON (Management of Optical Networks) has developed a concept for the management of optical WDM (wavelength division multiplexing) networks based on the TMN architecture. This concept comprises the operation, administration, and maintenance (OAM) mechanisms as well as an information model specified in GDMO (Guidelines for the Definition of Managed Objects). A prototype network called MOONET has been installed which extends over about 500 km and connects sites in Germany and Austria. In this network, the relevant components of the management concept are implemented in hardware and TMN software. At present, field trial experiments are being carried out in order to evaluate the management concepts under realistic conditions of network operation. This contribution describes the management concepts in terms of the functional architecture, the OAM concepts, and the information model. The infrastructure of the field trial is explained and an overview of the experiments is given. On the WDM layer, experiments on configuration and fault management are performed, where the focus is on fault management. Furthermore, aspects of the interworking between the WDM layer and ATM as a client of the network are studied.

This paper presents first results of the European research project MOON. It is organized as follows. As a starting point, basic concepts of all-optical networks which are relevant for management are described. The results are compared with the Synchronous Digital Hierarchy (SDH) which is the state-of-the-art transport technique. Then, the general architecture for a TMN conforming management of all-optical networks is illustrated. As a main point of the paper, the impact of transparency limitations on transmission, OAM (operation, administration, maintenance), and management is discussed. A functional architecture will be presented which describes the network in a formalized way. Based on this description, different approaches for the transmission of OAM overhead are addressed. The information model of MOON is described and compared to the SDH model. Finally, concepts for the implementation of the management system are presented.

A case study shows that an optical wavelength division multiplexing (WDM) network can be employed in a metropolitan network in a cost effective way. In part, cost savings are realized due to the total number of line terminals required and the fact that the dimensions of the electrical nodes decrease when exploiting optical cross connects (OXCs) to a large extent. Optical WDM rings are also an important building element when designing a metropolitan network. A number of the properties of WDM rings are classified, resulting in eight different ring architectures. Additional requirements arise when considering ring-to-ring connections. The extent of the rings chosen for the case study is validated from the transmission point of view by a simple model. Finally, as an alternative to an all-optical approach, an opto-electrical approach is presented.