Important Tests For Measuring VoIP Quality
You say you have been living under a rock and you are not familiar with broadband Speed Testing? Allow me to explain… Speed Testing is a important tool for measuring bandwidth speeds. This is especially important when preparing for a VoIP migration, or any other broadband dependent application… My preferred speed test site is Speedtest.net. This broadband speed analysis tool allows anyone to test their Internet connection. Ookla Solutions provides this service for free to anyone curious about the performance of their connection. Their technology is used to perform over one million speed tests every day.
The Speed Test site allows you to test multiple sites to and from hundreds of locations around the world. For the test I ran for this example, pictured above, I chose the closest, recommended server, which happens to be located in Phoenix, where Chromis Technology is based. As you can see, the result from my location is quite good, I get almost 20MB downstream, and 6.5MB upstream with reasonable Ping times. Very healthy for a VoIP connection.
But as we have all learned over the years, a solid connection with good bandwidth is only part of the VoIP puzzle… So that’s why Ookla created Pingtest.net. This test takes speed testing a step further by testing Ping, Jitter and Packet Loss – each critical to understanding the true quality of a broadband connection. But what do these mean? Let’s define these terms and relate them to a real time application such as VoIP.
Packet Loss – The percentage of packets sent to a server that never arrive. If I am speaking the sentence: “Chromis Technology is a Phoenix, Arizona VoIP Company” over a VoIP connection and the packets that contain “Phoenix, Arizona” never arrive, my sentence might play out as “Chromis Technology is a {silence} VoIP Company.”
**Ping **– The time it takes for a packet to travel from your computer to a server and back. Ping tests measure for Latency by determining the time it takes a given network packet to travel from source to destination and back. Physical distance, the number of router hops, encryption, and voice/data conversion all impact latency. A good broadband Internet connection typically results in ping test latency of less than 100 ms, often less than 30 ms. A satellite Internet connection normally suffers from latency above 500 ms. In our VoIP scenario, this is typically a SIP endpoint such as a Polycom Telephone and server you are connected to, such as Switchvox. So the greater the ping time and latency, the more likely you are to have over-talking (when one caller talks before the other caller is finished).
Jitter – Jitter is the variance in measuring successive ping tests. Zero jitter means the results were exactly the same every time, and anything above zero is the amount by which they varied. Like the other quality measurements, a lower jitter value is better. And while some jitter should be expected over the Internet, having it be a small fraction of the ping result is ideal. Most VOIP endpoint devices have jitter buffers to compensate for network jitter. Callers experiencing jitter on a VoIP call will notice delays in the conversations.
So while these tests are important, it’s also critical for me to point out that they are not the end all/be all solution to be used when designing your VoIP setup. But they are very powerful place to start yourself out towards a successful VoIP implementation. Chromis Technology, using BroadSoft Packetsmart VoIP testing equipment, can provide a detailed analysis of your LAN/WAN to help assess and resolve potential network issues before deploying VoIP services. For more information about how Chromis Technology can help you mount a successful VoIP implementation using our network assessment tools, please contact us at 602.357.8070.