Software Defined WAN is easily the most mature flavor of SDN. Consider how many large organizations have already deployed some sort of SD-WAN solution in recent years. It’s common to hear of organizations migrating dozens or even thousands of their sites to an entirely SD-WAN infrastructure, and this suggests that SD-WAN is no longer an interesting startup technology but part of the mainstream of networking.


The reason is clear to me. SD-WAN provides immediate benefits to a business’s bottom line, so from a business perspective, SD-WAN just makes sense. SD-WAN technology reduces complexity, improves performance and greatly reduces cost of an organization’s WAN infrastructure. The technology offers the ability to replace super-expensive private MPLS circuits for cheap broadband without sacrificing quality and reliability. Each vendor does this somewhat differently, but the benefits to the business are so palpable that the technology really is an easy sell.


The quality of the public internet has improved greatly over the last few years, so being able to tap into that resource and somehow retain a high quality link to branch offices and cloud applications is very tempting for cost-conscious CIOs. How can we leverage cheap internet connections like basic broadband, LTE and cheap cable yet maintain a high-quality user experience?


Bye-bye private circuits.


This is the most compelling aspect for using this technology. Ultimately it boils down getting rid of private circuits. MPLS links can cost thousands of dollars per month each, so if an SD-WAN solution can dramatically cut costs, provide fault tolerance and retain a quality experience, the value is going with all public internet connections.


Vendors run their software on proprietary appliances that make intelligent path decisions and negotiate with remote end devices to provide a variety of benefits. Some offer the ability to aggregate dissimilar internet connections such as broadband and LTE, some tout the ability to provide granular QoS over the public internet, and some solutions offer the ability to fail over from one primary public connection to another public connection without negatively affecting very sensitive traffic such as voice or streaming video. Also, keep in mind that this is an overlay technology which means that using SD-WAN means your transport is completely independent from the ISP.


Sweet. No more 3-year contracts with a monolith service provider.


Most SD-WAN vendors offer some, if not all, of these features, and some are going a step further by offering their solution as a managed service. Think about it: if your company is already paying some large ISP thousands per month for Ethernet handoffs into their MPLS cloud, what’s the difference with an SD-WAN managed service handing off a combination of Ethernet, LTE, etc. interfaces into their SD-WAN infrastructure?


Especially for small and medium-sized multi-site businesses, the initial cost of switching from managed MPLS to a dramatically cheaper managed SD-WAN provider is nothing compared to the savings over only a few years of savings from dropping private circuits.


For organizations such as high-transaction financial firms that want to manage their entire WAN infrastructure themselves and require almost perfect, lossless connectivity, SD-WAN may be a harder sell, but for most businesses it’s a no-brainer.


Picture a retail company with many locations such as a clothing store, bank, or chain restaurant that needs simple connectivity to payment processing applications, files, and authentication servers. These types of networks would benefit tremendously from SD-WAN because new branch locations can be brought online very quickly, very easily, and much more inexpensively than when using traditional private circuits. Not only that, but organizations wouldn’t be locked into a particular ISP anymore.


This is mainstream technology now, and it’s something to consider seriously when thinking about designing your next WAN infrastructure. It’s cheaper, easier to deploy, and easier to switch ISPs. That’s the real value of SD-WAN and why even huge organizations are switching to this technology in droves.