CapEx/OpEx Evaluation of Circuit vs Packet Switched Optical Networks

Future telecommunication networks will be designed to guarantee energy-efficiency and sustainability. Optical networks, given their capability to switch and transport large traffic amounts for a relatively-limited energy consumption, are expected to play an increasingly important role in the evolution towards energy efficiency. While traditional optical network design strategies are aimed at minimizing Capital Expenditures (CapEx), i.e., the cost associated to network equipment, several research studies have recently proposed novel strategies targeting the reduction of Operational Expenditures (OpEx) mainly identified with the network energy consumption. We compare two possible switching paradigms in optical networks, i.e., circuit switching (at the optical layer) and packet switching (at the electronic/IP layer). For each of them, we first provide novel network design strategies that minimize CapEx or OpEx and then we quantitatively identify and discuss under which conditions (network size, load, etc.) one paradigm is more convenient than the other from a cost and/or power consumption perspective.