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5 criteria for application-aware SD-WANs

Sep 26, 20184 mins

SD-WANs are not a panacea to all application performance problems. An application-aware network adds the intelligence to the network to optimize all applications under all conditions.

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Over the past five years, SD-WANs deployments have skyrocketed. And for good reason: They increase network agility and cut the cost of network transport.

One common myth about SD-WANs, however, is that they improve application performance. They certainly can under some circumstances, but there is no guarantee they will under all situations. SD-WANs address only part of the transformation of the network to becoming a digital enabler. SD-WANs must now become smarter, or “application aware,” to optimize user experience, improve customer service, and increase worker productivity. 

The requirement to have an application-aware network has never been more urgent, as application performance has a direct impact on a company’s top and bottom line. For example, according to an Accenture survey, 66 percent of millennials have changed their brand loyalties because of a bad user experience. Also, a recent ZK Research survey found that workers are 14 percent less productive than they could be as a result of poor application performance. Make no mistake; poorly performing applications are costing companies today.

Application awareness maximizes SD-WAN value

An application-aware network can identify and classify applications and then apply the appropriate optimization techniques to ensure optimum performance per user. The diverse types of applications — real-time, streaming, cloud, and others — require different optimization methods, so it’s important for the SD-WAN solution to support a wide range of network performance improvement features, including the following.

5 criteria for application-aware SD-WANs

  1. Application visibility understands who is using which applications and how these are performing. Also, operations teams need end-to-end visibility to quickly focus on where problems are occurring and speed up the time to resolution. Visibility should be thought of as the foundation for a high-quality user experience, as IT professionals need to know what applications are running and how they are performing to deliver the best user experience.
  2. Application quality of experience (QoE) controls sets priorities that match business objectives and prioritize critical business applications over recreational ones. Without this capability, network engineers would need to manually adjust the network as the network environment changes. This might have been sufficient a decade ago when changes were infrequent, but the environment is changing too fast for manual processes. Application QoE conditions the application traffic to dynamically mitigate any application performance problems that arise from network congestion.  
  3. Dynamic path selection ensures application flows get the best available network path based on their priorities and live network traffic conditions. This improves application performance and availability by routing traffic over different links when network issues arise. This is something that does require some homework as from vendor to vendor, the way dynamic path selection functions do vary widely. The technology should continually check multiple link characteristics to make the right decision and work on a per-app-session basis. Dynamic path selection is particularly beneficial for real-time applications, such as Skype for Business and video.
  4. WAN security secures applications delivered over internet links. The rise of hybrid WANs means more companies are doing local internet breakout at the branches, changing the security paradigm. This drives the need for businesses to deploy security tools at the edge or in the cloud. Application intelligence can provide a map of how to direct traffic to use the security tools most effectively. Whether terminating IPsec tunnels, connecting to a secure web gateway or filtering traffic at the edge, security is critical to an SD-WAN, but without application intelligence in the network, businesses may not be maximizing the efficiency of their security tools.
  5. WAN optimization improves the performance of non-real-time applications, reduces bandwidth usage, and delays network upgrades. WAN optimization is the biggest no-brainer for SD-WANs and is a core component of being application aware. The use of it can significantly reduce bandwidth usage and optimize performance over slow links without having to upgrade the network. In fact, many businesses have told me they have been able to delay a network upgrade by as much as three years by deploying SD-WANs. Also, when using broadband with SD-WANs, the bandwidth can vary quite a bit between DSL, cable, wireless, and others. WAN optimization can deliver uniform application performance across the network, even when the sizes of the pipes are different.

For application-aware, it’s all five criteria or bust

When discussing this topic with network professionals, I’ve been asked which of the five criteria is most important, and my answer has remained the same: “All of them.” Each feature performs a different function and plays a key role in being application aware.

For example, WAN optimization improves the performance of non-real-time apps, and dynamic path selection makes real-time applications work better. Think of application awareness as providing the intelligence that is required to take SD-WANs to the next level. All five must work together to meet the demands that digital transformation brings.


Zeus Kerravala is the founder and principal analyst with ZK Research, and provides a mix of tactical advice to help his clients in the current business climate and long-term strategic advice. Kerravala provides research and advice to end-user IT and network managers, vendors of IT hardware, software and services and the financial community looking to invest in the companies that he covers.

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