When test tools were first created for networking products, most of them didn’t take into account the need to test application traffic – perhaps because they didn’t need to. Two decades ago, YouTube didn’t exist. If you had said “SaaS” to someone, they would have looked at you like you were crazy. VoIP or video as an application? Dream on.

Today, there are more applications than we can count, and new ones are being released all the time. To further complicate matters, application traffic is wildly unpredictable. Any number of variables can affect performance and reliability. So why are we still testing networking products the same old way?

As it turns out, the usual suspects are to blame: We’re busy. Deadlines are tight. Teams are stretched thin. Our tools are limited, so we make do.

Networking technology has made huge leaps since the '90s, and our approach to testing should take this leap as well. Take VXLAN: Here’s an emerging technology that demonstrates why application-level testing is vital.

VXLAN is an overlay technology that makes it easier for network engineers to scale and manage networked cloud computing environments. By allowing for better segmentation, it provides more flexibility for isolating cloud applications or tenants.

As a Layer 2/3 technology, there is a perception that VXLAN doesn't need application testing; after all, it’s just a Layer 2 overlay on a Layer 3 network. But this perception is dangerous, because it simply isn’t true. VXLAN utilizes existing IP infrastructure, merging new with old for improved scaling and functionality. The benefits it provides are compelling — but any time you merge technologies, complications occur.

Let’s keep in mind that the ultimate goal for VXLAN or any other networking technology is to effectively carry application traffic from one point in the network to another. Therefore, it stands to reason that the only way to ensure that VXLAN can deliver on that goal is to test with real application traffic. Standard Layer 2/3 testing does not adequately demonstrate whether VXLAN is fulfilling its ultimate goal, because there is no real end-user application involved in the testing, and hence it is inadequate.

No network administrator wants to be surprised by snafus on the network — and application-level testing is the only way to prevent those surprises from happening. Most standard testing methodologies generate plain vanilla TCP/UDP traffic or just “blast bits” to check basic performance and functionality.

That’s good, but it’s not enough. You need an approach that allows you to isolate different parts of the network and simulate realistic application traffic across these points, including voice, video, and even encrypted traffic. When you do find trouble spots, you want the ability to debug them fast — grouping results in a logical way that lets you isolate the user, tunnel, device, or application that is under-performing.

Here’s how VXLAN benefits from application-level testing:

• Verify vMotion functionality. One of the key reasons to deploy VXLAN is to better facilitate vMotion. But how can you be sure vMotion is working properly? The only true test is to ensure that the application(s) being vMotioned does not degrade or become unavailable. The only definitive way to test this is to send real or realistic application traffic across your VXLAN-enabled network, vMotion it, and verify that all is well.
• Prevent applications from suffering increased latency. Increased latency can wreak havoc on latency-sensitive applications that are omnipresent in all enterprise networks, such as synchronous data replication or video. How can you be sure that encapsulation and decapsulation of VXLAN tunnels is not creating unacceptable levels of latency? The only way to have total confidence is to run latency-sensitive application traffic over the VXLAN enabled network and measure the relevant metrics such as mean opinion score (MOS) for quality of experience.
• Keep encryption running smoothly. Security reasons make SSL or IPsec encrypted traffic a must-have in most networks. You may assume that VXLAN won’t cause any problems with encrypted traffic, but why take the risk? Test your VXLAN infrastructure with encrypted traffic to make sure any applications running inside the encrypted tunnels are not being degraded.

VXLAN is still a new and emerging technology, and we’re still learning about the challenges associated with it – which makes application testing all the more vital. Don’t be lulled into thinking that this Layer 2/3 technology doesn’t need application-level testing. It does. By testing VXLAN often with realistic application traffic at various points, you’ll be able to realize the benefits of VXLAN more quickly, and minimize interruptions and downtime.