Network management Toolkit

Foundry boss looks at Ethernet future

Peter Judge ZDNet.co.uk

Published: 14 Oct 2002 16:32 BST

Ethernet will continue to surprise us, with a 40Gbps version likely, and an unexpected appearance of 10Gbps on copper cables, according to Bobby Johnson, CEO of Foundry Networks. Meanwhile, Gigabit and 10Gbps Ethernet are finding uses in the enterprise -- which is just as well for Foundry, since the company has specialised in Gigabit Ethernet, and found the majority of its market in dot-com service providers -- until recently.

"Ten Gigabit is already running on copper -- for distances of around 15 ft," said Johnson. "We need this to be 100 metres, but there should be products that do this in around two years."

In fact there are two separate efforts to put 10Gbps Ethernet on copper cabling -- even though when the standard was first finalised, it was widely believed that a worthwhile transmission distance would never be achieved on copper cables. A November meeting of the IEEE 802.3 group which co-ordinates Ethernet standards, will help determine which becomes a potential standard.

"The first is being called 10GBase-CX4, the second 10GBase-T," according to Intel Fellow Bob Grow, chair of the IEEE 802.3 working group, a principal architect at Intel and a former chair of the 10 Gigabit Ethernet Alliance. The 10GBase-CX4 suggestion uses XAUI (10 Gigabit Attachment Unit Interface, pronounced "Zowie"), which is defined in IEEE Std 802.3ae-2002.

As with other Ethernet standards, XAUI re-uses physical interconnections designed for other networks, in this case 10Gbps Infiniband and Fibre Channel, which can be run on short copper cables. "10GBASE-CX4 is targeted to rack and stack interconnection within an equipment room, by running XAUI over 4X Infiniband cables and connectors," explained Grow. This will require some additional specification to the 802.3ae; standards work on this could be kicked off in November and would be completed quite quickly, said Grow. Among the companies working in this area are Xilinx.

Meanwhile, 10GBase-T refers to efforts to get 10Gbps running on conventional twisted pair cables. "This effort would take more time to generate a standard than 10GBASE-CX4," said Grow. A standards effort for 10Gbase-T might run it over 100m lengths of "horizontal cabling" (specified in TIA 568 or ISO/IEC 11801), but might settle for a shorter distance.

Before a standards effort is started, the proponents have to convince the IEEE802.3 that the effort is worthwhile.