10 Gigabit getting ready to go copper

While the fiber-based 10G Ethernet standard is less than a year old, the IEEE already is moving to create a copper-based version of the 802.3ae standard.

Two study groups formed in November are working on copper versions of 10G Ethernet with different approaches. One camp is backing a proposal for 10GBase-T, or 10G Ethernet over twisted-pair wiring, such as Category 5e or Cat 6 cabling. Another group is exploring 10G Ethernet over four pairs of twin-axial cabling - used previously in older IBM midrange server connectivity. Both versions are expected to reduce the cost of 10 Gigabit technology, which ranges from $17,000 to $80,000 per port.

While twisted-pair is the convention for wiring corporations with copper cabling, electrical limitations on the cabling could complicate the 10GBase-T.

"We were really pushing the limit of [twisted- pair wiring] technology when we hit 1000Base-T," says Brad Booth, chair of the IEEE 10GBase-T study group, and a chief architect with Intel. Booth says he does not expect to see 10GBase-T gear available until 2004 or 2005.

A twin-axial cable, with its thicker-gauge wiring, has been deemed less tricky. A draft is expected by March, and a standard could be set by year-end.

The two variations also would have different roles, Booth says. With twin-axial, connection ranges would be short - between 50 and 100 feet - with the target application being short switch-to-switch or server interconnects in a data center. Cat 5 or 6 would be able to reach about 300 feet, which could let users to run 10G Ethernet across installed horizontal structured cabling plants.

Whichever standard wins, a copper version of 10G Ethernet is seen as a way to keep down the price of the technology.

"Historically, copper has been the lowest price and highest volume" media for Ethernet, Booth says. Experts estimate that a copper version of 10 Gigabit could be 50% less expensive to produce than fiber-based switch ports and network interface cards.

Vendors also say they are readying products. Chip makers such as Solarflare and Broadcom have said they are developing copper-based 10 Gigabit silicon, and switch maker Force10 Networks hints that it could have a copper-based 10-Gigabit blade by year-end.