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Are we there yet? The Road to 10G Ethernet Part 1

Ian Yates

It seems only yesterday that Ethernet took the big leap from 100 Mbps to 1Gbps, yet 10 gigabit Ethernet is already on the agenda. This search networking special explains the current status of the standard and offers a roadmap to get your business onto the fastest Ethernet highway yet.

Despite sales figures from last quarter which predict an annual US$1b spend, 10-gigabit Ethernet has only been officially available since 2002 and then only over fibre-optic cable. However, as soon as the ink dried on the IEEE 802.3af standard, cable and switch vendors promised, and then delivered, the same speeds over copper cable, while hoping that a standard would soon arrive to back up their claims and provide essential interoperability. Last June, IEEE 802.3an got the nod as the approved way to send data really fast over twisted-pair copper cable.

The good news therefore is that there is now an official standard, to be known as 10GBase-T, making it possible to choose cables and components with a high degree of confidence. The bad news of course, is that anyone with an already installed 10G Ethernet over copper solution might find their choices limited when it comes to expansion and interoperability. About now would be a good time to re-read those warranty documents carefully.

The new standard requires copper cable with a 500MHz bandwidth, but a lot of 350MHz Category 6 cable has been pulled already. The augmented "Category 6a" cable also provides immunity to alien (from

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nearby cables) crosstalk at the 500MHz level, because susceptibility to interference from nearby sources is the limiting factor for distance. Earlier forms of Cat 6 cable will most likely still operate to some extent with 10G Ethernet, but will be unlikely to achieve the 100m distance laid down in the standard, probably petering out at 55m. Some vendors are using "Category 7" as the name for the new cable, and since bigger numbers sound better it seems likely that others will follow.

The latest Cat 6 cable is thicker, to provide further isolation from nearby cables, and strict attention needs to be paid to radius bends, as well as the tension applied when pulling the cable. For these reasons, certification really will matter this time around, and installers will need to come up to speed quickly or risk losing market share. Analysts are predicting that most new installations will specify 10G-capable copper, even if there are no plans to use the high-speed capacity in the near future. Cable plant needs to last 5 years as an absolute minimum and within that timeframe 10G is expected to rule the backbone, with 1G being the de-facto desktop standard.

Right now, only grid computing endeavours are using 10G everywhere. The rest of us are using it for backbones, server farms and storage networks. The move to copper is expected to increase the number of businesses which are prepared to embrace the highest-speed Ethernet due to the lower costs of acquisition, installation and termination. The price per port of active devices is expected to tumble along with the increased implementation of 10GBase-T, with predictions of $1500 per port within the first generation of fixed-configuration switches. Although there are 10G switches on the market now, they will at least certification and in some cases upgrading, to comply with the 10GBase-T distance standard of 100m.