Along with the expansion of Internet users and the innovation of Internet applications

the scale of the Internet increases rapidly.High performance and reliability requirements of the Internet will bring in the huge power consumption and inefficient energy usage

which increases operation costs of the Internet and restricts its scale.Moreover

the rapidly increasing carbon footprint of the Internet will aggravate global warming.Researchers have proposed many energy-saving technologies in the Internet.This paper first presents the significance

feasibility and research scope of energy conservation in the Internet;We then focus on studying the energy-saving technologies for routing devices and protocols in the Internet

and survey

analyze and compare some of typical schemes in details;Meanwhile

we propose the power consumption model of routing devices and leverage the tradeoff analysis to guide the research of energy-saving routing devices and protocols in the Internet;Finally

some open issues and future directions in this area are discussed.