Engineers push beyond 10Gbit Ethernet limit
At three separate industry events last week, engineers said they are gearing up to deliver in 2011 chips that can handle serial data streams running at 25Gbit/s to drive next-generation 100- and 400Gbit/s networks. But they say it's still a mystery how—or if—they can deliver follow-on components for the terabit networks today's Internet data centers are already demanding.
The kinds of jobs required to run today's Web 2.0 services such as Google and Facebook can completely overwhelm current 10Gbit/s Ethernet links in the warehouse-sized data centers those companies use. Such data centers could use hundreds of 100Gbit/s Ethernet links today, although standards for such networks are still being completed.
"There are no 100Gbit Ethernet products I can use now," said Donn Lee, a member of the networking team at Facebook, speaking to the Ethernet Alliance at an event here. But the kinds of MapReduce/Hadoop jobs Facebook developers and others use "can drive tremendous needs for bandwidth with just the press of a button," Lee said.
Facebook is not alone. Google and others have said they will need Terabit Ethernet products as early as 2013.
That's because today's big Internet data centers use three or more tiers of networks to aggregate and link traffic from warehouses of standard PC servers. Today's servers typically use Gbit Ethernet on their motherboards, driving demand for 10Gbit links to aggregate traffic from seven-foot racks of servers and Terabit Ethernet to link multiple rows of racks.
Server motherboards are just starting to migrate to 10Gbit Ethernet links, driving needs for even faster aggregation nets. With networking pressures rising in the data centers, carriers and service providers have been joining chip and systems companies at the table in next-generation Ethernet standards meetings.
For example, Amazon.com, Comcast, Google, Netflix, Sprint and Verizon have participated in the IEEE 802.3ba group that is setting the 100G Ethernet standards. "This is very different from when we were looking at 10Gbit Ethernet," said John D'Ambrosia, chairman of IEEE 802.3ba who has worked on several generations of Ethernet standards.
Bumping physical boundaries
Some veteran networking experts are looking at the future beyond 100Gbit/s and scratching their heads.
"We are starting to press some physical boundaries such as switching speeds of silicon and traces on printed circuit boards—and all of this is changing the cost dynamics," said Bob Grow, an Intel and IEEE executive who has worked on Ethernet standards and products since the Mbit generation.
In past generations, engineers solved the problems by packing more transistors in transmit and receiver circuits. They relied on the trend that the costs of those transistors became negligible within one or two generations of finer semiconductor process technologies.
Thus end users got 10x the bandwidth for essentially the same price every two years or so. Engineers may not be able to bank on that trend for the terabit generation.
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