Ethernet Alliance pushes for 40G spec

The Ethernet Alliance has demonstrated versions of Ethernet with faster speeds, lower power and new features, and kicked off talks aiming to rally support for a 40G serial Ethernet standard at the annual Interop show in Las Vegas last week.

The efforts show Ethernet is moving forward on several fronts despite the economic downturn which could lower spending on the technology as much as 20 percent in 2009. "Even in a downturn, Ethernet shows signs of growth with new technologies and new markets," said Brad Booth, chairman of the board of the Ethernet Alliance, an industry group promoting the technology.

The Ethernet Alliance is sponsoring demos of three technologies aimed to advance today's 10G Ethernet. The technology has been slow to take off to date in part due to the power and cost of silicon as well as the need for new copper cabling.

The Alliance will show for the first time silicon from three vendors supporting 10GBase-T, the specification for running Ethernet up to 100m at 10Gbit/s over enhanced copper cables. The demo includes transceivers from startups Aquantia, Solarflare and Teranetics.

Having chips from three vendors "is a good sign we are getting more of these parts and players into the market and people getting to power numbers that are getting into the sweet spot," said Booth.

Today's transceivers consume more than 5W power. Aquantia announced earlier this month it is working on a 40nm design that could hit 2.5- to 3W in a chip it hopes to sample late this year.

Some say it will require 32nm process technology to get the chips down to the 1- to 2W level needed to be used on mainstream motherboards. Power requirements for 10GBase-T "depend on who you are talking to," Booth said. "If they can get 2.5- to 3W range that's pretty viable," he added.

Broadcom has announced 10GBase-T parts, and Marvell is believed to be designing silicon for the spec. "It would be awesome if we could show four or five vendors" with silicon in demos late this year, Booth said.

On the optical side, the Alliance also showcased also demonstrate SFP+ modules at Interop. The modules aim to deliver a lower cost, power and size optical link for 10G Ethernet and 8Gbit/s Fibre Channel.

A final vote on the SFP+ spec could be taken in June, opening the door the modules that can pack as many as 48 10G ports in a 1U-sized chassis, Booth said.

Pre-standard FCoE
The Alliance also will demo systems using a pre-standard version of the Fibre Channel over Ethernet (FCoE) specification for running Fibre Channel storage traffic over Ethernet, typically at 10Gbit speeds. The demo uses a reference design from Fulcrum as an FCoE switch linked to a storage array from NetApp, a new member of the Alliance.

Separately, Infiniband chipmaker Mellanox Technologies demonstrated what it calls Low-latency Ethernet at Interop. It uses a 10G interconnect with Infiniband-like RDMA characteristics to reduce latency to three microseconds, aiming at uses such as FCoE.

"Low latency Ethernet enables end users to derive tangible performance benefits from transaction intensive applications while reducing power and consolidating their SAN (FCoE) and LAN (10GbE) traffic on lossless 10 Gigabit Ethernet," said Michael Kagan, chief technologist of Mellanox in a press statement.

The FCoE standard is based on enhancements to the Fibre Channel spec by the T11 committee as well as complex work to create a lossless version of Ethernet as a transport. The later work handled by the IEEE 802.1 group is still in process and may not get ratified until next year.