Efficient network upgrade based on a WDM optical layer with automatic protection switching

Summary form only given. Wavelength-division multiplexing (WDM) is now recognized to be a promising technique for expanding the capacity of existing communication networks. Recently, robust network architectures for reliable high bandwidth networks have been designed. We shall briefly overview the automatic protection switching scheme (APS), present a new approach to optical network design, and investigate the impact of this architectural option on the network cost from the operator point-of-view. APS relies on pre-planned end-to-end routes with a service restoration time of 50 ms (e.g. SDH self-healing rings).