Optical path cross-connect system scale evaluation using path accommodation design for restricted wavelength multiplexing

The optical path (OP) technology, which employs both wavelength-division multiplexing and wavelength routing, will be the key to enhanced network integrity and an ubiquitous broadband integrated services digital network (B-ISDN) in the future. To construct the OP network, path accommodation design that can solve simultaneously the problems of path routing and wavelength assignment must be established. Since optical wavelengths are scarce resources, even with state-of-the-art technologies, the available number of wavelengths that can be multiplexed into a fiber is restricted to a relatively small number. This entails space division multiplexing with multiple fibers in the link in order to accommodate the large number of paths within a link. This paper proposes novel OP accommodation design algorithms that can heuristically establish wavelength paths (WPs) or virtual wavelength paths (VWPs) in the network, where each link is composed of multiple fibers. These algorithms minimize the average number of fibers (in other words, cross-connect ports) handled at the WP/VWP cross-connect nodes and enable us to obtain the required OP cross-connect (OPXC) system scale at each node in WP/VWP networks. Algorithms that consider failure restoration are also proposed. Some WP/VWP accommodation designs over a polygrid network are simulated using the proposed algorithms. The difference between the WP and VWP schemes in terms of the required OPXC system scale with and without considering failure restoration is quantitatively evaluated for the first time.