Green backbone optical networks: The way forward

Optical transport networks have been considered as one of the dominant energy consumers in the modern Internet, wherein the design toward green communication with awareness of energy saving has received growing attention from both industry and academia. This article reviews green designs in the Internet optical transport backbone, particularly on the current progresses in the development of various energy-saving strategies, such as optical bypass configurations and turning off (or sleeping) equipments, as well as the impact on network survivability and security, and renewable energy use. The article will also discuss how the network control plane should be extended to support the energy-saving functionality in the context of Generalized Multi-Protocol Label Switching (GMPLS).