SDN: What it Means, Max Hype Level Achieved and Code Words

The SDN washing is reaching new heights.  Apparently, I missed the memo that all companies were doing SDN two years ago.  The WSJ published a piece on SDN.  With all the SDN washing and the WSJ article, I think we might have hit the peak (i.e. inflated expectations) of the Gartner hype cycle for SDN.  As another example, here is an email that is representitive of about five emails I have received over the past month requesting the same.  The ironic aspect of this email is readers of my blog know that I have been posting the answers to these questions for over year.


Hi William,
I work at XXXX with XXXX, I think we may have actually met [in the past]. I came across Plexxi in my readings on SDNs. I am trying to work the implications across the value chain of SDN, for instance where will it be adopted, what does it do to traditional networking world, what are the implications for chipsets, modules etc.   Was keen to hear your views on it and get more familiar with Plexxi; any way we can try a call soon? Thanks.



My view of SDN is different than most.  That was the subject of my post prior to Structure.  When I look at how SDN is defined today, I call it the neoclassical definition or view of SDN.  Neoclassical SDN is concerned with the separation of control plane and the data path and how there can be APIs that allow a central controller to inject forwarding decisions.  I think there is a little if any chance of mainstream adoption for neoclassical SDN.  What will happen is new networks will be built and they will be built using some aspects of neoclassical SDN, but components of the solution and the application of these components will be different than what is generally available at present.  My definition of SDN is:

  • Computation and algorithms, in a word math. That is what SDN is.
  • Derive network topology and orchestration from the application and/or the tenant.  This is how SDN is different from switched networks.
  • Ensure application/tenant performance and reliability goals are accomplished.  This is part of the value proposition.
  • Make Network Orchestration concurrent with application deployment. This is what SDN is for.
  • A properly designed controller architecture has the scope, the perspective and the resources to efficiently compute and fit application instantences and tenants onto the network. This is how SDN will work.

All of the SDN articles and emails coming out the research world are really code words for an soft economy.  Business is soft, so let’s blame and hype SDN.  Much the recent SDN talk is really dancing around the underlying point of SDN.  SDN is not about network programability.  SDN is not about APIs.  SDN is not really about retrofitting legacy networking equipment with APIs and replicating old technologies in new wrappers.  The problem that has been growing over the past 18 years (note this is the era of switched networks) is the problem of IT OPEX.  There is no Moore’s Law for OPEX in world of IT.  Companies have dealt with it through several strategies with one of those strategies being outsourcing.  The thinking here was that companies could cap or at least predict their IT OPEX by outsourcing networks over to firms who would manage their network as well as others; thus allowing the outsourcing firms to get to scale.  The companies outsourcing get a fixed operating cost line, reduce headcount and create a lean organization.  Good in theory, but the result has not been as expected – it has been disappointing.  This is clearly my view that is only validated by my in person observations of the market.

When I look at how SDN will develop and I look at companies like Nicira, I understand the implications on the network.  The problem being addressed is the problem of OPEX and in part CAPEX in terms of customers asking do I need to upgrade now or can I wait?  In terms of SDN, the inverted Moore’s Law curve for IT OPEX is the driving force around the concept of SDN.  SDN is one possible tool to reduce OPEX.  The interesting part that I have found over the past 6-12 months is that IT leaders are exploring SDN as means to deploy new networks, but differently and for the first time in more than a decade they are thinking about tackling the OPEX curve and SDN holds promise as a strategy or tool in this objective.  As we close out the era of switched networks (1992-2012) and begin the next era of networking we have part of the market that will go for IT outsourcing to the cloud provider.  I still see this market segment (outsourcing group) as the broader SMB market served by cloud providers.  The high end of the market will build and deploy their own data centers using the post neoclassical definition of SDN.  I think the real SDN market develops in two segments: cloud providers and high-end enterprises deploying a hybrid utility compute DC.  My time line looks like this:

  • 2012 is the proof of concept (POC) year for SDN.  In 2012 we will see the first SDN proof of concept networks in the deployment range of 250-1000 10G servers.
  • 2013 is the year that at scale SDN builds start transitioning from POCs.  I think we will see SDN networks that scale up to 10,000 10G servers by mid to late 2013.
  • 2014 is the first big bang year.  2014 will be the year that we go to hyper scale and build DCs with 100k 10G servers, minimal hops, no OSR in a post neoclassical SDN world with controllers.

As always, this is just a blog and it is very possible that I am incorrect.


7 thoughts on “SDN: What it Means, Max Hype Level Achieved and Code Words

  1. Pingback: Inconvenient Truths, SDN, Innovation and Other Ramblings « SIWDT

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