IT Innovators: Using SDN Models to Increase Availability of Services

Here's another key reason why SDN should be on your radar.

While much has already been written about the benefits and key value propositions of Software Defined Networking (SDN), I’d like to add one more to the list: using SDN models for increasing availability of services.

Let’s take a step back here for a second. What’s the most important thing for network administrators when they onboard a new service? The answer is availability. They don’t want – and in truth can’t afford – for that service to go down, no matter what. Unfortunately, that’s not always a realistic expectation, since all too often the networking gets in the way and it can cause things to go down.

Redundancy offers one way to deal with this issue, but that comes with a hefty price tag. Just imagine you have one hardware load balancer and you want to go buy another for redundancy. You can buy it, of course, but it’s a pretty expensive proposition. And what is the degree of availability you should have? Should you have 2, 3 or even 5 load balancers? Then there’s the issue of what to do with your physical switches and firewalls. What is the degree of redundancy that you need?

These are challenging questions, indeed. Luckily, an SDN model can help. By using Network Function Virtualization (NFV) models in a SDN, you can virtualize some of these components—the load balancer, firewalls, and all kinds of appliances. You essentially then gain the ability to scale out your network. You might not get the raw power of scale that you would get from a hardware appliance, but you can certainly get to the same numbers by just bringing up more instances. And, you can scale out dynamically.

The beauty of this approach is that you can also scale in as well. Why is this important? Just imagine that it’s tax season and your company needs a significant number of more load balancers and web servers to handle all of the traffic that’s coming in. Once tax season ends; however, your company no longer needs that infrastructure. With the SDN model, it’s no problem. You simply scale the network back as needed.

This combination of being able to scale out and in dynamically gives network administrators the optimal flexibility to figure out how much redundancy they want to have in the network to ensure service stays up and that the network is able to keep up with demand. They can have a network controller that can spin up multiple instances. And, they can have load balancers that are load balancing multiple front ends or web servers, and as many of those as they want. They can then load balance the load balancers themselves, so they can have multiple load balancing multiplexers. They can also have multiple gateways, multiple NICs and multiple switches.

And what does all this mean? It means that the virtualized network components can essentially be taken down one at a time, as many as possible – and service will still remain up. That’s a huge benefit for today’s network administrators and another good reason why SDN should be on your radar—assuming it isn’t already. If you have any thoughts on this topic, drop me a line at In the meantime, for a look at past and future blogs on a whole range of IT-related topics check out this page.

This blog is sponsored by Microsoft.

Cheryl J. Ajluni is a freelance writer and editor based in California. She is the former Editor-in-Chief of Wireless Systems Design and served as the EDA/Advanced Technology editor for Electronic Design for over 10 years. She is also a published book author and patented engineer. Her work regularly appears in print and online publications. Contact her at with your comments or story ideas.


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