Cross-layer approach for performance evaluation in IP/GMPLS over WDM network

Current trend of integrating IP and WDM technology is to evolve core IP networks away from the overlay model and towards more integrated solutions - IP/GMPLS over WDM, which enables more efficient usage of optical bandwidth. However, the removal of ATM and/or SONET/SDH layers implies possible coupling of optical and network layers. This work aims to raise the necessity and elaborate a cross-layer approach of counting optical impairments into the performance evaluation of IP/GMPLS over WDM network. Normal procedure to calculate the network performance always takes one assumption for granted - traffic transmission in underlying optical network is perfect. However, the removal of SONET/SDH layer implies its error detection/correction function of is no longer used, which may result in useless information received by destination node. We set up a model and present a three-step cross-layer approach for analyzing the performance of IP/GMPLS over WDM network. The performance of IP traffic with and without considering optical impairments are compared and the numerical results demonstrate the network metrics, in terms of effective normalized throughput, are indeed affected by the characteristics of the underlying optical layer.