SD-WAN: What is it and What Does it Mean?

Posted by Ken Zrobok on Jul 15, 2016
Ken Zrobok
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Software Defined Wide Area Networking or SD-WAN is new evolving technology that has resulted from the Software Defined Networking advancements in the last few years that were found mostly in Data Centers. SD-WAN uses software and cloud based services to help companies deliver a simplified delivery of services across the WAN. 

Why Should I Care About SD-WAN?

The simple answer is, if this technology can benefit your organization, lower your costs and/or improve your network functionality, then you may want to learn more about it. 

The first thing you need to understand is “Are We a Fit for SD-WAN”?

Are We a Fit for SD-WAN?

  • Do you have any Software as a Service (SaaS) applications that your company uses today?
  • Do you have a backup internet connection if your primary connection goes down?
  • Does your organization use a Hosted Voice or Video solution?
  • Do you have multiple offices that need to be connected?
  • Would you like to have multiple carriers for redundancy and not be locked in to a single carrier?
  • Are you running any Real Time Traffic (Voice or Video) across your WAN?

If you answered yes to any of the above points, an SD-WAN solution could benefit your company. Now let’s break down each point above.

Existing SaaS Applications

An SD-WAN solution has the ability to apply policy based instructions to your traffic over multiple connections. In addition the SD-WAN solution has an Internet Gateway in the cloud with direct access to the other hosted SaaS environments. This means that not only can you provide your SaaS applications a Quality of Service (QoS) policy but you can improve the route your traffic takes and reduce hops and latency.

This type of QoS can also be applied to companies that have deployed Unified Communications as a Service (UCaaS), such as a Hosted PBX or Hosted Video services.

Backup Internet Connection

Most companies will have a secondary connection, for when the primary internet connection goes down.  This is like insurance, you pay for it even though you may not be using it.  The primary circuit going down is not usually a question of “Will we lose our primary connection?” but more of a question “When is it going down next?”

Companies can usually afford these expensive routers at their Head Office but when it comes to the smaller remote offices, they tend to have “less fancy” equipment.  Therefore, if the primary connection goes down, there have to be a manual intervention to “re-point or re-route” the existing traffic to the backup connection.

With an SD-WAN solution, you do not require any manual intervention because the SD-WAN uses both connections concurrently.  The solution will monitor and route traffic based on the best path possible at all times.  When one of the links/connection goes down, all the traffic automatically re-route over the remaining working links.  Therefore you will have an Active/Active internet connections that dynamically route without any user intervention.

Multiple Branch Offices

WANs are complicated for most companies because it involves Carrier Circuits, Service Level Agreements (SLAs), remote office hardware (Router/Firewall) and either a Fully Meshed or a Hub and Spoke Wide Area Network. Each time that a decision is made to change carriers, add additional services or even add a new location all the aforementioned areas are required to be updated/changed.  Every time a stable network is modified there is a very good chance that something won’t come back online or there will be an impact to business via some functionality or feature loss.

Read Case Study: SD-WAN For 19 Connected Locations

An SD-WAN solution can be added to your existing network services, as well as it will automatically create all the connections and routing to all the other locations.  Now changes in the WAN in either additions or changes are less risky because of the automatic deployment and connectivity that SD-WAN offers.  In addition to the automatic deployment and the ability to use all network circuits in an Active/Active scenario, there is less dependence on expensive carrier circuits.  Companies can source local inexpensive internet connections with an SD-WAN solution and either migrate from an expensive MPLS circuit or choose the less expensive circuits with the same results.

Real Time Traffic (Voice/Video) across the WAN

In an SD-WAN solution, QoS policies by default prioritize voice and video traffic across all internet circuits.  This may be any combination of MPLS or non MPLS circuits.  Due to the more expensive nature of an MPLS circuit, policies may also be applied to restrict low priority traffic from utilizing the more expensive MPLS circuit. What this allows is customers that can have finite control on what traffic traverses which connection as well as report on how well the circuits are performing.

With the addition of SD-WAN customers can look at deploying voice and video across non MPLS circuits and still receiving the same type of QoS that MPLS type circuits provide. 


This is just a sample of features that an SD-WAN solution would provide for an organization.  This type of technology evolution is a welcomed addition to our industry and helps us remove more dependence on our less than agile “friends” at the Carrier(s).

Tags: SD-WAN