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  • Writer's pictureDean Anthony Gratton

Software-Defined Networking: 101

I thought I’d take a look at software-defined networking (SDN) this month, since it’s another topic I regularly see across Technically Speaking and a subject that’s been populating most technology news headlines recently. Like my previous article covering network functions virtualization (NFV) which was published last year, I wanted to not only understand the subject matter better myself, but share with you the fundamentals of the concept as well as its supposition.

Outsourcing Your Data

So, I began with undertaking some initial research and started to pull out what SDN was all about and what, ultimately, it wants to achieve. At first glance, I was amazed that, like most technologies, it seems SDN is not entirely new and started to surface circa. 1995, although I’m not going to delve into its history here.

I’d like to start with describing a couple of reasons as to what has fueled the need for ideologies such as SDN and NFV. Well, in short, cloud computing and data centers have amassed in recent years and have been predominately responsible for accelerating SDN. The large collection of networked servers widely used by organizations across the world for applications or services, remote storage, processing or simply distributing data itself have grown exponentially. Likewise, both consumers and businesses have also created an enormous demand for outsourcing data storage for personal and business use. More specifically, with an internet of things (IoT) data-driven model, we will inevitably see an explosion of data akin to a ‘big bang’ – anyway, I’ll save that for another column!

Remotely Access Your Digital Stash

So, personally, my entire digital music collection is in the cloud, occupying 160Gbit of my 1Tbit allowance. In fact, all my research work, columns, books, illustrations and other paraphernalia are also stored in the cloud. As such, all my work is stored securely and, of course, as I purchase new music, it’s automatically synced, meaning I always have access to my digital world irrespective of location, so long as I have that all-important internet connection!

Okay, so this comfortably works for me in my 1Tbit digital universe but, as an organization or large enterprise, we’re probably talking about applications or services and data storage that offer customers enterprise-grade outsourcing services. In short, we are talking about petabytes or possibly, dare I say, exabytes of capacity – yep, the latter is a denomination we’re not used to but, trust me, it’s coming!

Unpredictable Traffic and Unprecedented Demand on Services

What’s more, such data centers and cloud services, with today’s connectivity options, largely remain geographically uninhibited – in other words, as an individual or large corporation, no matter where you are in the world, you have access to your digital stash! More so, a business can choose to outsource its entire data center, for example, where numerous and scalable options are available, such as Google Drive or iCloud to Microsoft Azure or Amazon Web Services, enabling your organization to entirely outsource your cloud ecosystem.

For both consumers and enterprises choosing to outsource their applications, services and data, data centers and cloud services are nowadays typically plagued with unpredictable data traffic and often an unprecedented spontaneous demand on applications, services, storage and, ultimately, bandwidth. And, with an IoT data-driven model for consumers, industry and retailers, the demand is expected to explode. So, SDN was created and further accelerated in a response to accommodate this demand.

Soothing Rapid or Unpredictable Traffic Patterns and Demands

And today, SDN provides a solution to overcome limitations with existing network infrastructures. You see, in a traditional network architecture, these centers and services would respond to demand or expansion through physically upgrading the infrastructure, although this is an inevitably costly exercise; whereas, SDN offers a self-configuring, dynamic, flexible and adaptable method to ensure your infrastructure longevity, whilst easily adapting to current or future trends.

SDN is a whole new change to your existing infrastructure, which may require additional retraining and reconfiguration to your topology, for example. Nevertheless, there are numerous tools that simplify a homogenous ethos. SDN permits organizations to holistically adapt their networks without the need to physically add new hardware to the infrastructure and, as such, it can self-configure to accommodate traffic patterns whilst addressing peaks in demand. Ultimately, SDN is particularly suited for large data centers and cloud service organizations that regularly see rapid or unpredictable traffic patterns and demands.

Until Next Time …

I suppose the downside with SDN – something I have already touched upon, is that you have to reconfigure or restructure your infrastructure, since the dynamics of the SDN architecture are a tad different. You’ll need to implement the SDN protocol, which extends to including an SDN controller – this ultimately manages the interfaces across the three layers, namely the application, control plane and the infrastructure layer (or data plane).

As such, there is a requirement to use different services, as well as varying diagnostic tools and this is quite a daunting responsibility, since this change may result in a complete restructure of your business model. One such tool, OpenFlow, an SDN controller, achieves communication across all interfaces of your devices, although most organizations have now moved away from OpenFlow in favor of other controller management techniques.

So, this is where an ‘embracing new things’ Dr. G signs off.

Originally published in Technically Speaking.


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a technology influencer, analyst & futurist 

I dispel the rumours, gossip and hype surrounding new technology

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