INTEL HAS FORMED an open industry group with end-user customers, system vendors and optical companies to rally around a specification that addresses the "up to 2km data centre reach" for optical cables, called the 100G CLR4 Alliance.
Headed by Intel, the group's mission is to create open, multi-vendor specifications for small, cost-effective, lower power optical transceivers in data centres using duplex single-mode fibre, which is said to reduce fibre count by 75 percent, thus reducing costs.
"There are telecom centric optical transceivers today operating at 100Gbps, but their power, size and costs are non-starters for the new data centre. Thus, there is a huge gap that needs to be filled for reaches that span from say 100m to 2km. And that's the problem we are trying to address here," said the director of Photonics Research at Intel Labs, Dr Mario Paniccia.
The first issue that Intel said the alliance will approach is growth of data centre capacity.
"For any industry to expand there needs to be industry-wide specifications or standards that ultimately make things work better together and more importantly, drive down costs," Paniccia said. "Second, photonic communication is a great way to move data."
Therefore, the allience believes that the ideal communications standard is optical, due to its benefits for moving data further than electrical links, transmitting data faster and remaining unaffected by electro-magnetic interference (EMI).
"As we move from 10Gbps signalling to 25Gbps signalling, optical communication becomes even more important," Paniccia added.
The alliance is also pushing to make use of more space in data centres because they are becoming "massive in scale", requiring longer reaches for connectivity.
"This leaves an enormous opportunity to bring high-speed, low-power, optical links that can span up to [two] kilometres in modern data centres operating at data rates up to 100Gbps. That's more than 20 football fields," Paniccia explained.
Arista Networks' founder and chief development officer Andy Bechtolsheim, who previously co-founded Sun Microsystems, explained that the standard is urgently needed to fill a gap between the 100G SR4 standard, which only supports fibre spans of a few metres, and the 100G LR4 standard aimed at telecommunications firms. The latter supports fibre spans up to 10km, but is very costly, he said.
"When the IEEE [Institute of Electrical and Electronics Engineers] created the 100Gbps standard in 2010, it defined two optics: 100G-SR4 and 100G-LR4. Neither one addresses the needs of large DC operators who need to cover distances of 100m up to a kilometre or so, and power-efficiency, which existing standards are not meeting," Bechtolsheim said.
The transceiver modules in question are plug-in physical layer modules that terminate the optical fibre to a piece of networking kit such as a switch or router.
"The industry will transition to 100Gbps as soon as it becomes widely available, but what has been missing is cost-effective optics. Single-mode fibre currently goes out to 10km, but is very expensive. What data centres need is something in the 1-2km range that is cost effective," Bechtolsheim said.
Intel said it has received "overwhelming support" for the specifications in the last two weeks, and moving forward they will be supported by Dell, Ebay, HP, Arista, Oracle, Oclaro, Fujitsu and many others. µ
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