The increasing requirements for bandwidth drive the 100G Ethernet into use as quickly as possible. The major technologies supporting 100G Ethernet interface include the physical layer channel convergence technology, multi-fiber channel and Wavelength Division Multiplexing (WDM ) technology. The key technology for high-speed optical devices at the interface requires a breakthrough. The demands driven by the increase of interface rate require better packet processing and storage, system switching, and backplane technology. In addition, in the network, the transport problem of the new interface should be solved, including defining transport standards and pushing the development of key transport technologies. As far as the cost and requirements are concerned, the commercial application of 100G Ethernet is viable in Metropolitan Area Networks (MANs ).