Optical path layer technologies to enhance B-ISDN performance

Path layer technologies play a key role in the development of a powerful and failure resilient broadband integrated services digital network (B-ISDN). The authors discuss wavelength division multiplexing/frequency division multiplexing (WDM/FDM) techniques and demonstrate that optical paths can greatly enhance the path layer capability and, therefore, network performance. It is shown that effective network failure restoration can be achieved with optical paths. The applicability of the wavelength path (WP) technique to global area networks is revealed. WPs are applied to the national backbone network example to evaluate the required number of wavelengths and to identify optical cross-connect node requirements. A new optical path concept is proposed, i.e., the virtual wavelength path (VWP). In the VWP scheme, wavelengths are assigned on a link-by-link basis. The wavelength assigned to a wavelength path has only local significance. Significant benefits of the VWP such as the simplified path accommodation design within a transmission facility network and the reduced number of wavelengths needed, are elucidated