Issues and Challenges in Next-Generation Mixed-Line-Rate and Energy-Driven Optical WDM Networks

This article summarizes the main challenges that arise, and that need to be addressed in the core optical networks of the next generation, focusing on energy efficiency and awareness, heterogeneity of the traffic and the ever-growing need for transmission capacity. In all-optical mixed line rate (MLR) network, feasibility of a lightpath is determined by the physical layer impairment (PLI) accumulation. Contrary to PLIaware routing and wavelength assignment (PLIA-RWA) algorithm applicable for a 10Gbps WDM network, a new Routing, Wavelength, Modulation format assignment (RWMFA) algorithm is required for a MLR optical WDM network. Tremendous growth in the internet traffic has forced Internet Service Providers to increase the CapEx and OpEx. The major contributor to the OpEx is expenditure on the energy sources, which also results in large carbon foot print. Environmental concern and need for reduction in OpEx forces the service providers to look into energy efficient networks. Finally, the article identifies several open problems for future research.