Plexxi is integrating its products with a 3D MEMS optical switch from Calient Technologies to boost the scalability of data centers that use its software-defined networking technology.
Plexxi's top-of-rack Ethernet switches already interconnect with each other via a dynamic optical mesh based on wavelength division multiplexing (WDM). Plexxi's software-defined networking (SDN) controller can allocate bandwidth between its switches on an optical ring by manipulating wavelengths of light.
Micro-electromechanical systems (MEMS) are microscopic mirrors that can be manipulated with electrical voltage to create new optical circuits on a network dynamically. A Calient S320 3D MEMS optical switch has 320 input ports and 320 output ports. Inside the switch are two arrays of microscopic MEMS mirrors that create new optical circuits for data by changing their shape.
"By bending the mirrors on both sides with voltages, you can achieve full any-to-any connectivity in a pure photonic domain," said Daniel Tardent, vice president of marketing for Goleta, Calif.-based Calient.
The Calient S320 3D MEMS optical switch can allocate full any-to-any connectivity within a Plexxi ring, but it can also dynamically interconnect multiple Plexxi rings within a data center.
"We can take Plexxi rings and connect them with a Calient switch so the rings are now interconnected across a circuit-switched network" said Mat Mathews, co-founder and vice president of product management at Cambridge, Mass.-based Plexxi.
The 3D MEMS optical switch helps Plexxi overcome the fact that there are a finite number of wavelengths that its WDM rings can use to allocate bandwidth.
"If you need a lot of capacity between Plexxi boxes in positions one and five in your ring, [with WDM] you can just grab that particular wavelength that runs between those systems and you have a very low-latency path between those elements," said Eric Hanselman, research director for 451 Research.
However, sometimes the need for capacity between two switches on a ring will conflict with other traffic requirements, and Calient's technology addresses that challenge.
"At some point down the road you can do traffic analysis and say, 'Most of my traffic is between [switches] one and five, [and] I'd like to put those next to each other so I don't impact other higher capacity paths between switches two and six or three and eight.' The Calient system gives you the ability to change your optical interconnects. You can build some chunk of the ring so it's passing through the Calient switch and it can rearrange [which switches are connected]," Hanselman said.
Plexxi's control software can recognize when certain applications are going to have big traffic requirements and signal the Calient to dedicate a single-hop connection using MEMS mirror technology.
"Good examples are things like vMotion or backups -- things that are persistent flows where you can say, 'Here is what I need for this period of time,'" Mathews said. That persistent flow can get all the bandwidth it wants without affecting the rest of the network."
Plexxi's previous integration with application performance management vendor Boundary Software figures into this equation, Mathews added.
"Boundary helps us understand application telemetry data and gives us performance indicators," he said. "We'll be looking at real-time application performance information. When it detects a requirement for something like a more persistent connection between Plexxi rings, [our controller] will signal the Calient device to provision that connection."
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