Link utilization in survivable WDM mesh network

Protection and restoration are two techniques used in designing survivable Wavelength-division-multiplexing (WDM) networks. In this paper we propose new simple integer linear program (ILP) formulations for commonly accepted techniques such as, node-link and link-path model to allocate working and spare capacity in WDM mesh networks. Primary and backup lightpath allocation model is implemented by using two techniques such as, shortest path routing (SPR) algorithm and link utilization (LU) algorithm. LU algorithm is implemented with a dynamic link weight variable. In the same way spare capacity requirement is calculated for link restoration and path restoration model. Routing and wavelength assignment (RWA) is solved by wavelength continuity constraint. Multiple traffic patterns are generated using Poissons distribution. Simulation results validate that LU algorithm reduces link overhead marginally compared to SPR algorithm. Simulation is performed on widely used NSF network. We have identified the crucial links which are frequently used for traffic distribution.