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SD-WAN or WAN Optimization?

Joshua Dobies
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SD-WAN or WAN Optimization? I love that question. And, in order to answer it correctly, let me first dispel a common misperception. The question assumes SD-WAN and WAN Optimization are different solutions for the same set of problems. They are not. There may be some overlap between the two, but a lot less than you might think.

As with most questions, the answer depends on the problem and situation. Here’s a quick “decoder ring” that works 100% of the time to give you the correct answer:

Problem #1: Conventional Routers

Situation: “My fleet of conventional branch routers are too hard to manage, especially now that I have more apps in the cloud and different types of WAN circuits at remote sites.”

Solution: This one is easy. Get rid of your old routers. Invest in SD-WAN. Just make sure it’s an SD-WAN solution that’s equipped with an enterprise-class routing stack.

Problem #2: Latency 

Situation: “My app is running too slow even though there’s unused WAN capacity.”

Solution: This one is also easy. SD-WAN won’t help. More WAN capacity won’t help. The poor app performance — response time and/or end-to-end throughput — is likely being dictated by latency’s effect on underlying network and application protocols. Use WAN Optimization. Specifically, use one that accelerates BOTH networking AND application protocols over long distance.

Like traffic on a highway, distance, capacity, and congestion impact how quickly and efficiently apps reach their destination.

Like traffic on a highway, distance, capacity, and congestion impact how quickly and efficiently apps reach their destination.

Problem #3: Bandwidth 

Situation: “My app is running too slow and I’ve run out of WAN capacity.”

Solution: There are actually three distinct scenarios you could be running into here. We’ll cover the scenario and solution for each one, and then show you a bullet proof way to know which scenario you’re actually in.

1) Scenario A: You’re out of bandwidth. But, it’s a red herring. The performance of the app in question is actually being dictated by latency, in which case adding more bandwidth will just add more cost.

Solution A: Use WAN Optimization. SD-WAN won’t help.

2) Scenario B: You’re out of bandwidth. And, the lack of bandwidth is the true bottleneck of app performance. However, there’s no good option to increase raw WAN capacity. No carrier provides a larger circuit for that location and/or it’ll take too long to procure and/or it’ll be too costly once it’s there.

Solution B: SD-WAN can’t help. Use WAN Optimization. Look for one that provides byte-level deduplication AND compression. With both techniques, you can virtually expand capacity by 4x, 5x, even 10x and more.

3) Scenario C: You’re out of bandwidth. And, the lack of bandwidth is the true bottleneck of app performance and procuring more WAN capacity is a cost-effective and timely option.

Solution C: Use SD-WAN. With one BIG caveat. MAKE SURE YOU’RE NOT IN SCENARIO A (i.e., make sure latency isn’t your real problem).

Finding the Root Cause

There are tools that can analyze packet captures from your network and tell you if your bottleneck is bandwidth or latency. Riverbed Transaction Analyzer is one of them. It can even help you determine if the problem isn’t in the network at all (e.g., it’s a client-side problem or a server-side problem).

In a nut-shell, make sure you know which problem you’re facing before you ask “Do I need WAN Optimization or SD-WAN?” Because what you really need is the flexibility to use either or both in combination whenever it makes sense.

The real problem you might be facing is that there aren’t many solutions out there that deliver both. Here’s an SD-WAN solution that combines enterprise-class routing, advanced SD-WAN, industry-leading WAN Optimization and Application Acceleration, and next-generation security. Like I said, I love that question.

 

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