What is a WAN Emulator?

Most organizations have multiple branches and employees access applications over Leased Lines, MPLS Lines, VPN over Internet Leased Lines and even VPN over broadband networks. In such a scenario, how would you ensure that the applications hosted in your data center will adhere to certain (minimum) performance levels for everyone?

Welcome the WAN Emulator.

To test different types of WAN links right from your data center/head office, you could connect the client as well as the server/application to the WAN Emulator – which simulates WAN conditions – and the application performance with each type of WAN Link can be tested/measured.

It is possible to configure the WAN Link with several parameters like type of WAN link, bandwidth, distance (latency), jitter, packet loss, congestion, throughput rate, background traffic, etc. using the WAN Emulator, in order to simulate various WAN scenarios. These parameters need to be measured and replicated from your branch office, telecommuter locations and certain assumptions on worst case scenarios could also be made.

The advantages of having an opportunity to do such testing right from the data center/HO is not only to enable faster roll-out of new applications, but also to help IT administrators test, optimize and improve existing applications. Testing apps is important because you’d want to know how your ERP/VoIP and other critical applications would impact users, especially the ones using low-bandwidth connections. Lost time (and hence productivity), especially during certain times when the network load is high (like month ends, for example) might cost the company more than you estimate.

How accurately WAN Emulators can simulate/emulate WAN conditions and network loads might be dependent on the settings and your measurements, but it will give a good idea about application responsiveness under different WAN conditions. Even partial deployment (for testing purpose) may not give the actual picture and administrators are almost always surprised after the complete roll-out!

There are hardware-based WAN Emulators and there are open source/software-based LAN Emulators. There are different models/different versions of WAN emulators that can emulate anything from a few kilobyte connections to tens of gigabyte connections. And there are ones that can simulate special conditions like IP ToS prioritization, periodic/burst packet-loss, etc.

How effective/accurate they are, I don’t know. But the product exists because it is satisfying a business need. Do you think it’s time to test a WAN Emulator? Maybe it is.

Reference/Further info:

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