Faster Ethernet round the corner

A high-speed Ethernet standard originally developed to run over fibre networks could eventually run over cheap copper cabling if the Institute of Electrical and Electronics Engineers (IEEE) adopts a new standards effort for 10Gbps Ethernet at its annual conference in Taipei, Taiwan next month. "Ten Gigabit is already running on copper -- for distances of around 15 feet," said Bobby Johnson chief executive of Foundry Networks, in a wide-ranging interview with Tech Update. "We need this to be 100 metres, but there should be products that do this in around two years." Key people in the Ethernet standards world have confirmed that two options will be considered in Taipei. One option, 10GBase-CX4, uses XAUI (10 Gigabit Attachment Unit Interface, pronounced "Zowie"), a standard defined in IEEE Std 802.3ae-2002, and used by Infiniband for short rack interconnects used in server rooms. The extra work to get 10Gbps on copper this way would be pretty minimal, said 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. Meanwhile, an effort to get 10Gbps running on conventional twisted pair cables is referred to as 10Gbase-T. "This effort would take more time to generate a standard than 10GBASE-CX4," said Grow. Both options will be discussed at the Taipei conference, and either or both could begin the slow process to becoming a standard. Meanwhile, the next speed jump for Ethernet could be a four-times multiple, rather than the traditional ten times, which has taken Ethernet from 10Mbps, to 100Mbps, Gigabit and now 10Gbps. Most Ethernet standards have reused physical specifications from other communications protocols such as Fibre Channel (Gigabit Ethernet) and SONET OC-192 (10Gbps Ethernet). However, there are no communication standards at 100Gbps, so Ethernet may simply adopt the highest available option -- SONET OC-768, which is 40Gbps. "Historically, 802.3 has been reluctant to do a four times multiple," said Grow. A four-times speed jump was proposed and dismissed after both the Fast Ethernet and Gigabit Ethernet standards, he pointed out. "But 10Gbps Ethernet is the first time we are at the same rate as the SONET world. Link aggregation is now the standard method for accomplishing 2x or 4x the data rate."

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