MIT’s Technology Review reports researchers from IBM (IBM), Intel (INTC), and the University of California, Santa Barbara have come up with a way to improve data transmission in data centers. Heather Zheng, associate professor of computer science at UCSB who led the research says wireless is the answer to the in-rack cabling mess usually found in data centers. In their paper (PDF), the researchers say that transmitting data wirelessly within a data center would be simpler than rewiring data for tech titans like Google (GOOG), Facebook, or Twitter.
Line-of-sight connections
The earlier challenge for multi-gigabit wireless in the data center was it required a line-of-sight connection to be useful. Achieving the required data center speed could not happen in the maze of metal racks, HVAC ducts, and electrical conduits that make up most data centers.
TR reports that the researcher’s solution is to bounce 60-gigahertz Wi-Fi signals off the ceiling, which could boost data transmission speeds by 30 percent. Stacey Higginbotham at GigaOm points out that this could result in data transfers up to 500 Gigabits per second. She says current Ethernet cables in data centers are generally 1, 10, or maybe 40 gigabits per second.
60-gigahertz Wi-Fi for servers
Ms. Zheng and colleagues used 60-gigahertz Wi-Fi, which has a bandwidth in the gigabits-per-second range and was developed for high-definition wireless communications according to TR. However, it has its limitations, says Ms. Zheng. To maximize the bandwidth and reduce interference between signals, it needs to use 3D beamforming to focus the beams in a direct line of sight between endpoints. “Any obstacle larger than 2.5 millimeters can block the signal,” she says in the TR article.
One way to prevent the antennas from blocking each other would be to allow them to communicate only with their immediate neighbors, creating a type of mesh network. But that would further complicate efforts to route the data to the proper destinations, Professor Zheng told TR. Bouncing the beams off the ceiling directly to their targets not only ensures direct point-to-point communication between antennas but also reduces the chances that any two beams will cross and cause interference. “That’s very important when you have a high density of signals,” she says.
Flat metal plates placed on the ceiling offer near-perfect reflection. “You also need an absorber material on the rack to make sure the signal doesn’t bounce back up,” says Ms. Zheng.
Wireless can add 0.5 terabytes per second
According to Technology Review, the UCSB team worked with Lei Yang from Intel Labs in Oregon and Weile Zhang at Jiao Tong University in Xi’an, China, to simulate a 160-rack data center to see how the system might work. “Our simulation shows that wireless can add 0.5 terabytes per second,” she says.
IBM is also looking into using wireless technology in data centers, Scott Reynolds, a researcher at IBM’s T.J. Watson Research Center in Yorktown Heights, NY, who has been developing 60-gigahertz systems told TR. “These data centers are just choked with cables,” he says. “And so every time you want to reconfigure one it’s very labor-intensive and expensive.” But one problem with turning to wireless transmission, he adds, is that “you need to have hundreds of these wireless data links operating in a data center to be useful.” Since 60-gigahertz Wi-Fi has only four data channels, it’s important to configure the beams so they don’t interfere with each other.
Mark Thiele, the EVP of data center technology at Switch Communications‘ SuperNAP data center, told GigaOm that the research is worth following as low-latency networking inside the data center can be a bottleneck today for applications that range from financial trading to trying to move gigantic data sets around.
TR reports Ms. Zheng and her colleagues are now working on building a prototype data center to put their solution into practice.
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Having just done a small data center cleanup, the idea is appealing. We pulled out 2 generations of cabling, IBM Type 1, and a bunch of Cat 3 multi-pair out from under the deck.
Ms. Higginbotham says the choice of 60 GHz for the data center is a smart move. Intel is pushing 60GHz for consumer use, under the WiGig brand (I wrote about WiGig in 2010 here). This means the chips would be cheap.
Some of the possible security issues raised by running Wi-Fi in the data center are tempered by using the 60Ghz range. She says if you are worried about someone standing outside the data center trying to eavesdrop on the data you are transmitting the 60Ghz, signals deteriorate rapidly.
Of course, change is hard and data center guys are going to have to learn wireless and top-of-rack switches would have to get radio cards installed. The Wi-Fi reflective panels would have to be installed on the ceiling of the data center and the servers would need a signal-absorbing surface so the Wi-Fi signals don’t continually bounce around the data center.
Just if you are confused about WiGig, Wi-Fi, and IEEE, EETimes says, “WiGig forged a deal with the Wi-Fi Alliance so its 60 GHz approach can be certified as a future generation of Wi-Fi. The group has aligned its technical approach with the existing IEEE 802.11ad standards effort on 60 GHz.”
Now if only they could do wireless electricity……..
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Ralph Bach has been in IT long enough to know better and has blogged from his Bach Seat about IT, careers, and anything else that catches his attention since 2005. You can follow him on LinkedIn, Facebook, and Twitter. Email the Bach Seat here.
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