Plexxi Inc., a Nashua, N.H.-based startup that is building a Software Defined Networking (SDN) optical switch, is back in the spotlight with the release of a new product, the Plexxi Switch 2. With the Switch 2, it's doubling down on its unique optical architecture for connecting data centers.

The Switch 2 is fun because it stirs up many of the existential questions about SDN, data centers, and whether a plucky startup can take down a giant networking company like Cisco (Nasdaq: CSCO) or Arista (Nasdaq: ANET). Such questions include: Can an optical switch also be SDN? Can you skip "leaf-and-spine" architectures? Should SDN controllers be open or proprietary? ...and many more fun puzzles for networking geeks.

Plexxi is different than most of the data center switches on the market in that: 1) It is built to connect in a "mesh" architecture, meaning that any switch connects to any other switch, rather than a tiered leaf-and-spine architecture in which smaller switches feed to bigger switches; and 2) It uses Plexxi's own "LightRail" system to build an optical, high-speed bypass circuit using Wave Division Multiplexing (WDM) technology that allows certain traffic to "skip" to the final destination without running through the switch fabric.

A little more about the box: The Switch 2 comes loaded with 48 to 78 ports of 10 Gbit/s, depending on the configuration, and two high-speed optical 480 Gbit/s LightRail ports (hence the Plexxi "2"), making for 2.56 Tbit/s in total switching capacity. This all fits in a compact, two rack-unit (RU) device.

A diagram of a potential design with Plexxi's architecture is below. The optical bypass circuit creates an optical ring between switches.

Why would you want to do this? Large data centers are messy places with lots of cabling and complex traffic patterns. The concept of this design is that it is more efficient for solving the "East-West" problem in data centers, in which most traffic is actually traveling between different server racks and switches inside a data center rather than outside the data center. Plexxi says that the optical bypass capabilities, along with the mesh architecture, will more efficiently move data around with less capital investment.

The big question is how that is all managed. Plexxi has its own SDN controller, which will analyze and route traffic through the switch according to the fastest route possible. Here we come to another existential question: SDN products are supposed to be open and interoperable. Plexxi has built a highly proprietary switch, with a weird architecture and its own proprietary controller. Will that fly in a world that is stoked about white-box switches built on commodity hardware?

That's CEO Rich Napolitano's mission. Napolitano has a long line of sales and marketing expertise at companies including Sun Microsystems (now Oracle) and EMC. He took over the CEO job from Plexxi founder David Husak last November, to rev up Plexxi's sales and marketing approach. Husak, a serial entrepreneur, said he was more comfortable in an engineering role.

Plexxi's position is unique, and it's also a big gamble. It has differentiated by focusing on optical switching technology and proprietary SDN software. By eliminating leaf-and-spine, it has a more modularº design that doesn't require two separate categories of switches. But at the same time, leaf-and-spine has become a standard data center architecture, and Plexxi is going up against the marketing power of Cisco and Arista.

Here's another interesting thing: The shipping hardware does not include software, which should get industry tongues a wagging about software disaggregation and whether or not Plexxi is an SDN company. The product is shipping now, and the price starts at $25,000, not including the software and integration licenses.

Plexxi Switch 2 Series will come in several flavors, including the following:

  • The Entry Series (2e), with 48 access ports, 6 QSFP fabric ports, and 240 Gbit/s of fabric capacity
  • The Performance Series (2s, 2sp), with 72 access ports, 4 dedicated Flexx ports, and 2 LightRail optical fabric interconnect ports delivering 240 Gbit/s of fabric capacity
  • The Performance Plus Series (2, 2p), with 48 access ports, 28 Flexx ports, and 4 LightRail optical fabric interconnect ports delivering 480 Gbit/s of multidimensional fabric capacity

Plexxi is probably best compared with some of the newer data center interconnect (DCI) optical switches, such as Infinera's Cloud Xpress. Cloud Xpress handles 1 Tbit/s of input and output capacity in two RUs.

There is no doubt that this is a cool and novel product -- if it works and the company can convince large data center customers to build their entire architecture around Plexxi. The unique design makes Plexxi either one of the most innovative optical SDN companies in the world or a strange white elephant.

It's not clear which yet, as Plexxi's customer list is not available. We are waiting to hear who wants to take the leap with Plexxi!