Green optical networks

In the last decade, the bandwidth of the Internet has grown by 50-100 times, thus more power consuming equipment (for example severs, amplifiers, routers,
storage devices and communication links) has been deployed, which has led to an increase in the power consumption. It is expected that one of the bottlenecks in the
development of ICT will be its power consumption. In order to overcome these problems, the “Green ICT” concept has been proposed which refers to attempts to achieve more energy efficiency and less pollution in the ICT industry.

Here, I focus on the design of optical networks taking power consumption into account, and develop new architectures, protocols, and algorithms to reduce the
power consumption of the network.

In this thesis, a novel Mixed Integer Linear Programming (MILP) mathematical model and a novel Renewable Energy Optimisation routing heuristic (REO-hop) were proposed for the energy efficient optical network employing both renewable energy and non-renewable energy. Furthermore, to reduce the power consumption of wavelength division multiplexing (WDM) networks that serve data centres, novel
MILP models were proposed to optimise the locations of data centres with and without renewable energy respectively. Moreover to exploit energy reduction in content distribution networks, we also proposed and evaluated a new approach (Energy Delay Optimisation Routing-EDOR). To incorporate the impact of topology, we studied energy efficient physical topologies design, considering
operational and embodied energy of network devices, by proposing a novel MILP model. The Routing and Wavelength Assignment (RWA) problem in WDM networks was reconsidered by jointly optimising delay, power consumption and
electricity cost using novel MILP models. To further reduce the power consumption of optical networks, novel MILP models for data compression and a novel routing
algorithm were proposed. In addition, a novel MILP model to investigate the energy efficiency of orthogonal frequency division multiplexing (OFDM) based optical networks was also proposed. Extensive simulations and analysis is provided and novel observations are presented in this thesis.