Support for 40Gb Ethernet standard stalls 100Gb plans

Global standards body the IEEE cannot decide whether the next Ethernet standard will be 40Gb or 100Gb because it's members, which include rival networking vendors such as Cisco and Nortel, are fighting amongst themselves.

The Higher Speed Study Group (HSSG) is working on defining the rules for a standard faster than the current limit of 10Gbps. The group consists of representatives from the world's top networking vendors, including Cisco, Nortel, Foundry Networks, IBM and Intel.

Ethernet has always been developed in factors of 10, from 10Mbps to 100Mbps to 1Gb Ethernet to 10Gb Ethernet.

But several figures within the HSSG want to make the next step a factor of four -- to 40Gbps. Others want to maintain the tenfold growth.

Proponents of giving Ethernet a fourfold speed boost argue that their concept is a necessary, simple and cost-effective step that has broad market potential. Fourfold increases are common among telecoms carriers who have based their networks on SDH, or synchronous digital hierarchy.

Those supporting a move to 100Gbps do not want to be bogged down by a second proposal.

Online discussions between HSSG members have been particularly heated, leading to accusations and name-calling.

The group will meet in San Francisco in July to try to resolve the issues. "All must work together to drive towards a consensus position, or the future of this group is clearly in doubt," said the chair of the HSSG, John D'Ambrosia.

Issues which must be overcome include ensuring that the higher speed is transmitted over the full 100 metres, and making sure that signals do not interfere with neighbouring cables, a phenomenon known as "crosstalk". Such high bit rates may also require considerable power, which could cause heat issues in comms cabinets.

A 100Gbps standard was originally slated to be finalised by the IEEE in either 2009 or 2010. 10Gbps is not yet widely deployed. Fidelity Investments and Somerfield, the supermarket chain, are two rare cases of UK businesses who have deployed the technology in their datacentres.

Richard Thurston reported for ZDNet UK from London