Affinity Networking Takes Center Stage

If you’ve been following Networking Field Day 5 or even the posts that I have derived from the content and presentations from the event, you realize that software defined networking was the major topic and theme of the event. Each of the vendors have their own approaches, special sauce, or interesting methods of using standards based protocols. Those in marketing might call this their unique value proposition. In many cases, the hardware to support the software defined networking or hybrid approach might be almost identical to that of traditional autonomous based approaches. Only one vendor fell far outside this criteria by designing radically different hardware and software solution that truly gave them a unique value proposition.

The SDN vendor I am talking about is Plexxi. What makes Plexxi unique is what they call affinity networking. The thought process is that endpoints in a typical network have different types of relationships. Plexxi calls these relationships affinities. In some relationships, devices talk a lot. In other relationships, the conversations may be short and sporadic. Maybe there are cases when lots of bandwidth is required, but not all of the time. Plexxi believes that if an application can understand these relationships, the network could be reconfigured to optimally support the needs of the devices and applications. The examples and statistics provided in the presentation were from a well design datacenter network.

At first glance, this seems far fetched. The reason it seems far fetched to us is that we tend to think of things in terms of our current technologies and their limitations. So while it seems that an application like the one mentioned could tell us where performance bottlenecks are, there would be manual intervention required to move the bandwidth around a datacenter or network. While understanding affinities could be quite interesting, it’s also a bit useless without a solution to dynamically move bandwidth around inside the network. Plexxi also foresaw this issue and did a pretty neat trick with their switches to overcome it.

The way Plexxi addresses dynamic bandwidth allocation inside their network is quite different. Basically, all Plexxi Switches are connected together to form a ring topology. The connections are fiber optic using coarse wavelength devision multiplexing. Bandwidth is allocated by pairing switches on a given wavelength or groups of wavelengths. When wavelength isn’t meant for a given switch in a Plexxi ring, it passes through that switch photonically to the next switch in the ring. By allowing software to control the wavelengths that switches should transmit and receive, the bandwidth can be dynamically moved around the network as necessary. The result is sort of like a layer 1.5 switch.

The video below describes affinity networking and how Plexxi solves challenges with SDN and CWDM

Marten Terpstra Describes How Plexxi Brings WDM To The Datacenter from Stephen Foskett on Vimeo.

Paul’s Take—As I mentioned earlier, Plexxi was the one Networking Field Day vendor that designed a radically different software and hardware approach to networking. Seeing a vendor think outside of the box is throughly refreshing. I believe some of the problems Plexxi is attempting to solve are certainly valid. The one thing I struggle with personally is whether an elegant solution like this can cost effectively build to overbuilding a network. While I think it is possible, time will tell how these technologies are adopted and implemented. I think one of the more interesting use may occur if high powered optics are used to create datacenter interconnects using the flexibility of a Plexxi ring.

Other Plexxi Videos From Networking Field Day 5

Information From Plexxi’s Blog

Plexxi Articles From Other Networking Field Day Delegates

Disclaimer: Plexxi was a sponsor for Networking Field Day 5. As a result, their sponsorship covered a portion of the cost of my travel and expenses associated with my attendance to this event. This article itself was written without any restrictions or requirement to do so. My opinions on this product are my own and are accurately reflected.


About Paul Stewart, CCIE 26009 (Security)

Paul is a Network and Security Engineer, Trainer and Blogger who enjoys understanding how things really work. With over 15 years of experience in the technology industry, Paul has helped many organizations build, maintain and secure their networks and systems.
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6 Responses to Affinity Networking Takes Center Stage

  1. We can help reduce cost in a number of ways:


    – Collapse tiers (fewer boxes)

    – Reduced cabling/xcvr requirements

    – Aside from fewer boxes to cable, there are 12 fiber strands in a given cable (MPO) in the fabric

    – For example, full optical mesh for 11 nodes = 11 cables


    – Overall, less heat production and electric consumption (fewer boxes)

    – Less components (boxes, cabling, xcvrs) means reduced on-going overhead of maintaining infrastructure

    – Automated capacity mgmt means.. even less cabling work and less impact from transient workloads.

    Integration with other vendors means many provisioning and troubleshooting tasks are automated or made easier. For instance, how does automated VLAN configuration work for you? Or automated discovery of affinities so things like storage traffic can automatically be identified and isolated from other kinds of traffic? Actually, there are so many things here that are possible (and already exist) that a illustrative conversation would take pages.

    In short, yes, I certainly believe our solution is cost-effective… and not just for capacity reasons.

    • Paul Stewart says:

      Can you share pricing or procurement information? For example, where would someone go to by Plexxi switches? What does the support look like? Does Plexxi deal directly or through partners? How the cost of a Plexxi switch compare to other vendors (with the full understanding there is some special sauce in your switches)?

      • Mat Mathews says:

        Hi Paul,

        Certainly. Our model is very simple. We price each switch (current Switch 1 is priced at $64k list) and a license for the Control SW ($5k per controlled switch). Note that even though our form factor is ToR, we are collapsing core/agg functions in a single tier approach, and our pricing includes all inter-switch optics and cabling, so in order to compare to other approaches you need to build and cable a leaf/spine or multi-tier network.

        We currently sell directly (or through select partners as required by customers) and offer our own services (our offerings are detailed here:

        Our goal is to be simple, not only when it comes to using our products, but also buying them, understanding our pricing, etc. We don’t do tricks like selling cheap empty switches and gouging customers on SFPs, SW add-ons for this and that, etc. Its clearly a departure from the norm in networking, but one we believe that customers will appreciate.

      • Paul Stewart says:

        Simple is good–always.

        On another note, I tried to by the Plexxi Airplane from your online store. It’s probably a good thing your site wouldn’t sell me one. My AMEX would have been declined when a $30,000,000 charge came through anyway 🙂

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