Designers rally around 25G, but next step still a mystery

Rick Merritt EE Times (02/08/2010 12:35 AM EST)

SANTA CLARA, Calif. — Electronics engineers are bumping up against the limits of their tools and techniques—and perhaps even physics--to keep pace with the rapidly expanding needs of an Internet-driven society.

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 25 Gbits/second to drive next-generation 100 and 400 Gbit/second 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 10 Gbit/s Ethernet links in the warehouse-sized data centers those companies use. Such data centers could use hundreds of 100 Gbit/s Ethernet links today, although standards for such networks are still being completed.

"There are no 100 Gbit 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 10 Gbit 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 10 Gbit 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 10 Gbit Ethernet," said John D'Ambrosia, chairman of IEEE 802.3ba who has worked on several generations of Ethernet standards.

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