Evaluation of IP over WDM Network Architectures

The commonly used IP-backbone network architecture of today is IP/ATM/SDH/WDM. This architecture has many redundant functionalities and is not optimized to transport IP traffic. New approaches for simplified network architectures try to eliminate redundant functionalities and to decrease the protocol overhead and thereby transport IP as efficiently as possible over WDM-based optical networks. EURESCOM project P918 Integration of IP-over-optical networks: networking and management investigated scenarios for optimized IP transport in WDM-based backbone networks. In this paper, three architectures, namely Gigabit Ethernet, Packet over Sonet/SDH and Dynamic Packet Transport are investigated and evaluated as an alternative to the IP/ATM/SDH/WDM architecture.     

Ten-channel coherent optical fibre transmission

A laboratory ten-channel coherent fibre-optic broadband transmission system is reported. The frequency-division-multiplexed optical carriers are separated by 6 GHz and are demultiplexed by a tunable heterodyne receiver having a sensitivity of -46 dBm at a bit error rate of 10-9. In this system a maximum number of 64 channels can be installed.     

Coherent optical multicarrier systems

Optical coherent multicarrier systems with highly selective tunable optical heterodyne receivers can be used for transmission and switching of broadband signals. Some technical solutions for coherent bidirectional subscriber lines, a ten-channel distribution system, and a switching setup with computer-controlled receiver tuning are presented. The laboratory experiments, including carrier-frequency stabilization, multiplexing, and demultiplexing, as well as the fiber components used, are described. The influence of fiber nonlinearities on multicarrier transmission is considered     

Coherent optical-fibre subscriber line

A laboratory bidirectional four-channel broadband coherent-type fibre-optic subscriber line (3.5 km) is reported. The carriers are centre-frequency-stabilised by a `heterodyne spectroscope? and demultiplexed by a tunable heterodyne receiver. In a very special state of the system, BER increases for nonlinear interaction between two counterpropagating narrowband lightwaves because of Brillouin scattering.     

Signalling experiment for optical frequency division multiplexedswitching systems

A signalling experiment for the optically switched data transmission of a 140 Mbit/s FSK modulated carrier is demonstrated. Optical control pulses determined in the frequency and time domains are generated and routed to an optically controlled bistable gate. The signalling, controlling, and switching remain completely in the optical domain     

Evolution of Terrestrial Optical System and Core Network Architecture

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.     

Simplified Design Approach of Reliable Transparent Optical Networks

Transparent optical networks will play an important role in the near future. The aim of this work is to provide a simplified design approach how to utilize the new feature “optical transparency” in WDM based optical networks. Therefore optical nodes and transmission links are characterized and a set of simplified parameters and rules describing the transparent sub-networks is presented. In this way the complexity originating from physical constraints is reduced substantially, simplifying the management of these optical networks and the physical parameters which will be implemented in the routing protocols. This contribution is a compendium of results of the BMBF KomNet project in the field of optical networks optimisation.