The role of network topology on the energy efficiency of IP-over-WDM architectures

Recently, researchers have focused their attention in investigating how much energy is consumed within optical Wavelength Division Multiplexed (WDM) networks, as energy requirement is becoming one of the main constraints in their design. Several solutions, typically exploiting optical switching technologies, have been proposed to reduce the excess of optical/ electronic/optical (OEO) signal conversions and electronic processing operations, which are known to be particularly power-hungry. However, most of the studies developed so far provide results that closely related to the specific case-study topologies under consideration, and the resulting conclusions may tend to be topology-dependent. In this paper, we consider a large set of randomly-generated topologies, characterized by different values of the network connectivity index (i.e., a measure of the average number of links per node within the network) and study the influence of this parameter on the energy consumption of different IP-over-WDM network architectures, namely Basic, Transparent and Opaque IP-over-WDM. We aim at quantifying how the the energy consumption of these different IP-over-WDM network architectures depends on network connectivity, geographical dimension and offered traffic.