Unless you're a very small business with a simple network and nothing in the cloud, you're probably already using software-defined networking (SDN) even if you don't know it. That's because whenever you sign up for a virtual server from a cloud-based infrastructure as a service (IaaS) player, you're really taking advantage of software-defined technology. When you sign on to Amazon Web Services (AWS), Google Cloud, or any of the other public cloud services, those virtualized instances are communicating with you and the rest of the world by using a software-defined network.
But that may not be the case in your own data center. According to some estimates, only about a quarter of on-premises networks are using software-defined anything and even there most of that usage is only on a partail or siloed basis. The reasons are many but mostly they boil down to one word: inertia. But there's another word that follows closely: fear.
What is Software-Defined Networking?
The traditional network that's currently in your data center and elsewhere in your company consists of switches, routers, and other network devices, each with its own, defined purpose. These devices contain their own management software, often prorietary operating systems, and, while they may be managed as a group using network management software, they're still independent devices subject to individual configuration issues, so they need a troubleshooting schema that can get very complicated very quickly.SDN puts the management of each of these devices into a dedicated layer that has an end-to-end view of the network, and even beyond the network if you're employing hybrid or service-reliant architectures. This layer also works on a functional level, so a software-defined router, for example, will route every packet from source to destination, choosing the best path for each. The resulting single-layer optimization means that what used to be difficult multi-layer tasks, like optimizing traffic planning is now much easier because the not only the traffic and management tools are at the software layer, the infrastructure is, too.
But you say that the network in your organization already works so why change it? "The old-fashioned way of using specific hardware locked you into a specific way of networking," explains Jack Gold, Principal Analyst at J. Gold Associates.
"SDN has a number of advantages," Gold said. "You can change network topology, identity, and firewalls, and put in antivirus or network monitoring in software." And because it's all in software, IT administrators gain not only the ability to quickly spin up virtual infrastructure, they can also store the templates for that infrastructure for even faster use in the future.The ability to change how your network is organized to meet your specific requirements is a huge plus, Gold said. Because it's done in software, it means that you can make changes whenever you need to, without having to switch out network hardware or appliances. Decide you don't like your network monitoring system? You can change it. Want a different anti-malware or security monitoring capability? You can change that, too.
Software Defined Cost Savings
One additional advantage SDN wilil deliver over the long term is cost savings. And for even medium-sized businesses, that can often add up to a lot of money. Gold said that, while there will be some upfront cost as you replace your existing infrastructure with hardware than is programmable, it will be cheaper over the long run."SDN should be easier to deploy from a resource perspective," Gold said, "because you don't need to find and hire an engineer with specialized hardware experience on your gear." Instead, you need a software engineer who can manage the hypervisor layer and the virtual infrastructure management tool, both of which are often based on Linux. In addition, the generic software-defined switches and other networking appliances are less expensive because they don't require proprietary licenses and support agreements. In the hands of experts, they're often safer, too, because such folk can literally build fully customized or app-optimized routers and switches from generic templates.
However, hype aside, SDN represents a paradigm shift in both network management and operations and any change like that requires careful planning. Gold provides four suggestions:
- "The first thing to do is think about what you want your network topology to be over the next couple of years. What features and functions do you think you'll need?"
- "Do you want to get it in-house? Do you want it as a service?" You can now get your networking as a service from a variety of vendors ranging from Cisco to HPE.
- "Check out what other people in your industry are doing. Check what they're changing or not changing."
- After that, Gold suggests you talk to a consultant, or if you have a dedicated shop, such as one in which your equipment is strictly from Cisco, then talk to Cisco, or whatever company provides your infrastructure. Most of them have made investments in SDN, so it's smart to look there early.
Gold said that the same calculations you used for deciding on a cloud service also apply to SDN. The bottom line is, which is cheaper? The monthly cost for networking as a service versus paying someone to manage your network, along with buying the infrastructure?
It's also important to know that you don't have to simply shut your operation down to make the switch. You can migrate your network in stages, bringing a software-defined network to those areas that need it the most, such as video, business-class voice over IP (VoIP), or to your virtualized servers in the data center, and then expand it to other parts of your legacy network over time.
This trend to software-defined networks is just starting. "Don't be alarmed if you think you might be behind the times," Gold said, "You're not alone."