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10 Misconceptions (and Lies) about SDN

by Andrew Lerner  |  March 19, 2014  |  7 Comments

(1)  SDN is no longer just for the Hyper-scale Web Companies or Academics – SDN started off as an academic exercise, and the earliest SDN implementations were in academic lab environments followed by the hyper-scale web guys where massive scale required a new approach to deal with 10,000+ network changes a day.  However, SDN implementations are now creeping into the mainstream, slowly but surely.  In fact, so much so that we’ve just published this SDN research aimed at mainstream enterprise.

(2) OpenFlow does not equal SDN – This is an older mentality but many folks still use OpenFlow and SDN interchangeably.  Openflow is a piece of the SDN story, as the first major southbound SDN protocol.  But Openflow alone is not SDN; SDN is much bigger.

(3) White-box switching is not the same SDN – These two terms are usually associated together, but they are not the same.  You can do white-box without SDN (just ask Dell and Cumulus), and you can do white-box within an SDN.  So while related, they are disaggregated (pun intended).

(4) Programmable Fabrics are nice, but they’re not SDN – Several vendors offer programmable Ethernet fabrics (sometimes with Open APIs) that are commonly referred to as SDN.  These are often very nice products that solve real customer challenges, but they are not SDN. 

(5) Programmatic control does not mean developers “own” the network – Network folks tend to get a little twitchy when they hear that SDN allows “programmatic access to the network”.  The typical response is “The last thing I want is developers controlling the network”.  This is not what SDN provides.  Instead, App Administrators can write APIs that communicate with the network controller via pre-defined templates or blueprints.  These functions on the controller are typically setup by a Networking person.  This isn’t the wild-west (sorry, application guys).

(6) VMware and Cisco are not the only SDN players – There is a lot of talk about VMware NSX versus Cisco ACI and their battle for data center networking influence.  However, there are a number of other players in the SDN space; including mainstream trusted IT vendors as well as startups (Juniper, HP, Nuage, PlumGRID, Midokura just to name a few).

(7) SDN is not a “network upgrade“– SDN is not something you slather across the network over a long weekend like a switch upgrade – it should be deployed opportunistically along with specific use-cases or drivers/pain-points.  Think of the way we deployed load-balancers in the 90s.  It wasn’t all the apps on day 1; it was the ones with specific requirements (i.e., scale/resiliency).

(8) Automation is not SDN – one of the most common benefits cited for SDN is networking agility – specifically the ability to delivery networking services to the business faster.  This can be delivered via orchestration and automation tools as well.  Hence, there is often confusion around orchestration and automation equating to SDN.  Like programmable Ethernet fabrics, automation can solve customer problems, but are not SDN.

(9) Any vendor who tells you they’ve been doing since before it was called SDN is probably lying – These are vendors who are now claiming to have been doing “SDN before it was cool“.  Some are telling the truth, but most are really spinning things. 

(10) SDN is not just about the network team – By definition, SDN blurs the silos between network, server, virtualization, and app teams.  It will be hard, “there will be blood”.  But it is long overdue in reality.

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Category: networking  sdn  

Tags: cisco  cumulus  dell  fabrics  openflow  sdn  vmware  white-box  

Andrew Lerner
Research Vice President
6+ years at Gartner
21 years IT Industry

Andrew Lerner is a Vice President in Gartner Research. He covers enterprise networking, including data center, campus and WAN with a focus on emerging technologies (SDN, SD-WAN, and Intent-based networking). Read Full Bio


Thoughts on 10 Misconceptions (and Lies) about SDN


  1. […] There hasn’t been a ton of adoption in “normal” networks, and there is a decent amount of confusion out there as […]

  2. Clive Hallam says:

    All valid points, I’d also add that many major networking vendors see an SDN strategy eating into their hardware sales, I have one large client whose reduced his hardware budget by 20% because he,s working towards an SDN strategy ! so vendors are looking to replace hardware revenues as well as tap in to others market share.
    Defining an SDN strategy for a business needs to be “whats right for the business” not blindly follow one vendors ideas that will inevitably be right for him !

    Have a look at http://www.tallacnetworks.com, Tallac are a startup, launched in the U.S. and soon to be in the U.K. as a springboard into EMEA, Tallac have lots of SDN experience in the team and many years of technical excellence, now focused around the mobility ( wireless ) aspects, just one area in the overall gameplan

    • Andrew Lerner says:

      Clive, thanks for reading/responding. We have the following published research aimed at vendors dealing with the issue(s) you identify

      Tech Go-to-Market: Breaking the Bond Between Software Value and Underlying Hardware Disrupts Long-Standing Sales Motions
      31 July 2013 | ID: G00255161
      Joe Skorupa | Tiffani Bova | Eric Goodness

  3. […] (i.e., aggregated), unlike the server world in which they are separate (disaggregated).  Another common misconception is that disaggregation (and white-box switching) is synonymous with SDN – it is not.  While […]

  4. […] addition, there are a number of general misconceptions around SDN with the result being that deploying SDN is a lot more art than science at this point. There is […]

  5. […] Over the past year, SDN awareness has skyrocketed in the mainstream. Most organizations are aware of the technology and now have plans to at least evaluate it. That said, there is still some confusion around the technology, and here are the top 7 misconceptions we see, versus last year. […]

  6. […] of SDN as an entirely new approach to how applications are routed and supported. It’s not a new coat of paint or a simple button that gets […]



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