Standards Projects Aim to Clear Up Bottlenecks in Data Centers

Enabling servers to handle increasing traffic

20 May 2013

As the number of people using Internet-enabled devices, services, and programs grows, so does the demand for faster connection speeds and more bandwidth. Making sure data centers can handle all the traffic is the focus of two IEEE Standards Association Ethernet projects.

IEEE Std. 802.3 does not currently support 100 gigabits per second (Gb/s) Ethernet operation on backplane media. IEEE P802.3bj is a new project within the IEEE 802.3 working group that is determined to define that capability for the Ethernet standard, as well as define operation over low-cost twin-axial copper cables.

The second project, IEEE P802.3bq, aims to tackle the future of server connections for Ethernet transmission over twisted-pair copper cable. Currently, the two most popular Ethernet options are 100BASE-TX (which operates at data speeds of 100 megabits per second) and 1000BASE-T (at 1 Gb/s). Volume deployment for 10GBASE-T has been anticipated for the past year. This new project will define Ethernet operation over twisted-pair copper cables at 40 Gb/s, and is targeting the data center application area, says IEEE Member John D’Ambrosia, chair of the IEEE 802.3 400 Gigabit Ethernet study group.

“These two projects actually span generations of technologies,” D’Ambrosia says. Employed by Dell Computer in Round Rock, Texas, he is in the CTO office and is the company’s chief Ethernet evangelist. “There is a refresh cycle going on right now in data centers that are progressing from deployment of 1GbE servers to 10 GbE servers.

Adds Adam Healey, an IEEE member and chair of the IEEE P802.3bj task force: “Companies want to know that as they invest in technologies for their data centers, there’s an upgrade path forward. IEEE P802.3bj is a fundamental technology that, when used, will be instrumental in driving the structure of new data centers or by increasing the bandwidth of existing data centers. It cuts either way.” Healey is a Distinguished Engineer with LSI Corp. of Newburyport, Mass.


Most of us hardly ever think of data centers, except when our e-mail system goes down, our Internet connection slows to a crawl, or our Facebook page freezes. But for practically any company, the centers have become crucial to operations.

“Consumers continue to access applications on the Internet via different devices at continually increasing data rates, putting more pressure on the infrastructure of many companies’ data centers,” D’Ambrosia says. “The number of servers, switches, and storage requirements in data centers is growing. As the main data center interconnect technology, there is an expectation that Ethernet will provide solutions to deal with supporting this increased traffic. Everything has to work together. When any of those parts choke from too much traffic, you have bottlenecks that cause problems in the services and affect the user experience.”

There are various architectures employed in data centers, using different switching configurations such as top-of-rack or end-of-row, and different styles of servers such as rack or blade models. New switches and servers are major investments, costing as much as tens of thousands of U.S. dollars.

A number of “greenfield” (think new) data centers are being built, and there are many legacy data centers that need to expand their bandwidth capabilities, D’Ambrosia says. The IEEE P802.3bj standard will provide a useful tool for both, Healey says. According to Healey, the standard will spell out a core, 100 Gb/s copper interconnect technology for inside the existing communications boxes and for short-reach box-to-box copper cabling.

The IEEE P802.3bj task force is defining a four-lane, 25 Gb/s electrical signaling architecture to support 100 Gb/s Ethernet operation across backplanes up to 1 meter in length and copper cable operations up to at least 5 meters long.

The project also supports energy-efficient Ethernet, which allows data centers—notorious energy hogs—to optimize their power usage. The standard will provide ways to power down ports when traffic is low, Healey says, such as during off-peak hours.

The IEEE 802.3bq project is designed to build upon IEEE 802.3 BASE-T technologies, which typically use server-uplink data rates of up to 10 Gb/s today, and represent millions of ports shipped each year.

“Because of the ability of current IEEE 802.3 BASE-T technologies to interoperate with legacy versions via the standard’s ‘auto negotiation’ feature and so support cost-effective infrastructure upgrades, extension to 40 GbE and higher speeds will be possible in coming years,” says Bill Woodruff, who chaired the study group that became the IEEE 802.3bq task force and is an associate product line director with Broadcom. “Our study group gauged the timing and needs of extending the standard for server connectivity and other applications.”

The next-generation BASE-T group has proposed several improvements, including an energy-efficient Ethernet feature; support of local area networks using point-to-point links over structured cabling topologies, including directly connected link segments; support of a data rate of 40 Gb/s; and defining a link segment based on copper media whose characteristics include four-pair, balanced twisted-pair copper cabling, with up to two connectors and up to at least 30 meters long. And it will define a single 40 Gb/s physical layer-supporting operation on the link segment.

“The applications driving bandwidth growth are only limited by someone’s imagination to figure out how to use the services as well as what services can be used with the underlying infrastructures that are in place,” D’Ambrosia says. “Ultimately, data centers will need to deal with this.”

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