Routing dependable connections in WDM optical networks

Optical networks employing wavelength division multiplexing (WDM) and wavel ength routing are a potential candidate for future wide-area networks. As t hese networks are prone to component failures and they carry a large volume of traffic, providing fault tolerance capability to them is an important i ssue. This paper considers the problem of establishing dependable connectio ns (D-connections) in wavelength-routed wavelength-division multiplexed net works with dynamic traffic demands. We call a connection with fault-toleran t requirements as a D-connection. We recommend using the pro-active approach wherein a D-connection is identi fied with the establishment of the primary lightpath and a backup lightpath at the time of honoring the request. Upon occurrence of a fault, a failed connection finds its backup path readily available, We develop algorithms t o select routes and wavelengths to establish D-connections with improved bl ocking performance. These algorithms differ in their performance and comput ational complexity, The algorithms use backup multiplexing technique to eff iciently utilize the wavelength channels, To improve fairness between depen dable and non-dependable connections, we propose a method called backup thr eshold. We conduct extensive simulation experiments on different networks t o verify the effectiveness of the proposed algorithms. (C) 2001 Elsevier Sc ience B.V. All rights reserved.