Copper 100G Ethernet?

* The movement for 100 Gigabit Ethernet over copper wiring

Yes, you read the headline right. There is a movement within the IEEE Higher Speed Study Group to come up with a standard to run 100 Gigabit Ethernet not just over fiber-optic lines, but also over copper wiring.

The distances that could be attained, as you might expect, are rather short.

To put the goal in perspective, the IEEE 802.3an 10GBase-T standard for running 10G over unshielded twisted pair wiring can stretch 100 meters and was once thought to be impossible, or at least severely challenging. The IEEE 802.3ak 10GBase-CX4 standard runs 10 Gigabit Ethernet over twinaxial copper cabling, but only over 15 meters or so.

The new proposal on 100G is for taking an approach similar to that of 10GBase-CX4, where twinaxial or coaxial cabling would be used, with the intention of using such connections pretty exclusively for connections between racks in a data center. The study group is talking about 5 meters to 10 meters as a maximum.

Mike Bennett of Lawrence Berkeley National Laboratory gave a presentation to the study group earlier this month in which he argued that the need for a copper 100G interconnect is there. Bennett often gives the IEEE the perspective of the leading edge of Ethernet use. He said there would be demand for 5 meters, but longer would be better. The distance just has to be long enough to get from one rack to another.

Others gave presentations stating that technical feasibility, economic feasibility and market potential would all be demonstrated - which means that 100 Gigabit Ethernet over copper could become a reality.

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