et community in the IEEE likes to move in steps of 10 (e.g., from 10 Mbit/s to 100 Mbit/s, then 1 GbE followed by 10 GbE). Given the increasing number of 10-GbE interfaces in the enter- prise environment and the need for the network operator community to transport these signals, it was only a matter of time before the subject of the next step came to the fore. Chapter 14 Next Generation Ethernet Driven by an explosion in anticipated bandwidth for all types of Ethernet networks, the IEEE created a High-Speed Study Group (HSSG) to identify the requirements and applica- tions and decide on the next steps. On the one hand there was a strong requirement from the data center applications side to introduce 40 GbE for high-speed computing/server applications while on the other hand the telecommunications community, driven by network aggregation applications, wanted to develop a 100-GbE solution. After some considerable debate, the HSSG has decided to combine both 40 GbE and 100 GbE into a single draft standard known as 802.3ba. The group has already set out a number of requirements, including Support for the 802.3 frame format. This is hardly surprising given the need for backward compatibility with installed base. For 40-GbE solutions, support for at least 100 m on OM3 multimode fiber, at least 10 m over a copper cable assembly, and at least 1 m over a backplane. For 100-GbE solutions, support for 40 km on single-mode fiber, 10 km on single- mode fiber, 100 m on OM3 multimode fiber, and at least 10 m over a copper cable assembly. It should be noted that ITU-T's Study Group 15 has also initiated work to examine how these new Ethernet rates should be supported by the Optical Transport Network (OTN), including extending the multiplexing hierarchy. There is an assumption that the solution developed by the HSSG should be compatible with the OTN hierarchy and vice versa. The work of these two groups is likely to continue into 2010, and it can be anticipated that there will be some significant engineering challenges along the 