A technical group working on the next generation of Ethernet has agreed to disagree and will now work on a single standard that covers both 40Gbit/s, and 100Gbit/s speeds.

The Higher Speed Study Group (HSSG), part of the IEEE (Institute of Electrical and Electronics Engineers), made the decision last week at its meeting in San Francisco after months of debate between backers of the two speeds. If the IEEE approves the move late this year as expected, a standard may be completed by mid-2010, said John D'Ambrosia, chair of the HSSG.

Ethernet has sped up by a multiple of ten several times, from 10Mbit/s to 100Mbit/s and ultimately from 1Gbit/s to 10Gbit/s, the current fastest version. Some HSSG members backed a similar boost this time and that 100Gbit/s plan appeared to have won out late last year. But others pushed for a 40Gbit/s standard.

Different applications were at the heart of the disagreement, according to D'Ambrosia. The need for speed is growing everywhere, but at different rates. While the data output of servers doubles roughly every 24 months, the amount of traffic on carrier networks is doubling every 18 months, according to D'Ambrosia. Members more interested in faster server-to-switch applications pushed for a 40Gbit/s goal, while those aiming at network aggregation and backbones favoured 100Gbit/s. The higher speed means more expensive and power-hungry equipment.

"I wouldn't say there was a fight. I would say there was an education going on and it got heated at times," D'Ambrosia said.

Now a single standard, to be called IEEE 802.3ba, will include specifications for both speeds. Each will offer a selection of physical interfaces: There will be specifications for 40Gbit/s links up to 1 metre long for switch backplanes, 10 metres for copper cable and 100 metres for multimode fibre. For 100Gbits/s, the group will standardise 10-metre copper links, 100-metre multimode fibre links and 10-kilometre and 40-kilometre distances on single-mode fibre.

It's the first time an Ethernet standards task group has pursued two speeds in one standard, according to D'Ambrosia. "One size doesn't fit all in this case," he said.

"I wouldn't say there was a fight. I would say there was an education going on and it got heated at times," D'Ambrosia said.

Now a single standard, to be called IEEE 802.3ba, will include specifications for both speeds. Each will offer a selection of physical interfaces: There will be specifications for 40Gbit/s links up to 1 metre long for switch backplanes, 10 metres for copper cable and 100 metres for multimode fibre. For 100Gbit/s, the group will standardise 10-metre copper links, 100-meter multimode fibre links and 10-kilometre and 40-kilometre distances on single-mode fibre.

It's the first time an Ethernet standards task group has pursued two speeds in one standard, according to D'Ambrosia. "One size doesn't fit all in this case," he said.