Plexxi Switch

The Plexxi switch is an offering from Plexxi networks that forms a part of their overall SDN package. This device differs from traditional hardware solutions in ways that are quite unexpected. Built on merchant silicon, namely the Trident II chipset from Broadcom, this device, known a Switch 1, offers 32 x 10GB SFP+ ports, 2 x 40GB QSFP+ ports in a 1 RU device. Switching capacity sits around 1.28 Tbps which provides a 3:1 ratio. With the Trident II chipset a technology called Smart NV allows VXLAN and VTEP support out of the box. This chipset can even blast 100 x 10GB ports which is quite frankly awesome.

Where the real difference in the Plexxi offering comes with the LightRail technology. This technology offers passive optical multiplexing IN the device. This allows for terabits of data across one single cable. Using up to 24 2-degree WDM fibers split across two groups, Plexxi Switch 1’s can form a number of physical topologies which very high bandwidth throughput. By building this technology inside the switch you essentially eliminate the need for old styled aggregation switching. A reduction in complexity, design, and TCO.

An alarm bell might ring with some of you thinking about your cabling passing through a switch? Fear not. Being passive pass through, the Plexxi Switch’s LightRail still functions when a device turns off or fails. You still can pass traffic through a device that is offline. With 24 fiber cores per link per switch, you many and varied number of paths to move data affinities* around to isolate a switch to be replaced. With 24 x 10GB fibres as mentioned in the Network Field Day 5 presentation, they are broken into a 12 east, 12 west layout. That is around 240Gb per switch and when you look at a 10 to 11 Plexxi switches in a ring you will be looking at 2.64Tb forwarding capacity!

With infrastructure patching literally in the switch and LightRail cables pushing terabytes of data a thought must be spared for design. It gets gosh darned simplified physically. One cable into the switch and one cable out of the switch.

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The NFD5 videos discussed in two parts – the hardware and the software. Within the hardware video they drilled the notion of a physical token-ring-esque network topology. This topology suits Plexxi well due to the fact you can pass through and terminate your fiber anywhere thanks to the passive pass through LightRail. Below is a Plexxi before and after diagram of their view.

When you have a larger Plexxi deployment the focus shifts from circles, to patching and joining multiple circles. Every single topology I thought about with a Plexxi Switch 1 made me think of the following.

I can see it now. Large datacenters as Venn diagrams. Not a bad design at all and when you couple the smarts of Plexxi Control into your network you start to get giddy.

I for one am very excited about what Plexxi is offering. Although Plexxi control is the heart of their offering, I thought it was important to look at the physical side first. The breakthroughs on merchant silicon are superb. The notion of cabling and patching inside the switch is ingenious. With data centers being distributed and fabrics being stretched like a hide across DC’s, over subscription seems to become accepted. With one cable you can move a vast amount of data between devices!

If you think this physical stuff is impressive, wait until you see Plexxi Control!

* Affinities and Plexxi will be discussed in the software blog coming shortly.

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