Is your VoIP call performing properly? Seems like an odd question, but there is a way to check, and make adjustments as needed.
MOS stands for Mean Opinion Score, and it is a five-point scale opinion score for rating VoIP transmission quality. MOS scores can be calculated by using the International Telecommunications Union (ITU) standards P.861 and P.862 or using ITU Standard G.107. Newer systems often have built-in tools for measuring call quality using MOS.
Most VoIP calls get a MOS score between 3.5 and 4.2.
There also is a second standard for evaluating VoIP call quality, known as the R-Factor. This is a 120-point scale, making it potentially more accurate.
When selecting a VoIP provider, it can be useful to investigate MOS and R-Factor scores to get a picture of how reliable the VoIP connections will be overall.
There principally are three call quality challenges that VoIP faces when infrastructure is not up to snuff.
First, there’s call delay, also known as latency. You know a VoIP call has delay when calling is not in sync and there’s the need to wait while the other person hears what has been said. In the early days of VoIP this was a common issue, although it is less common in 2015 as the industry and the technology in general has matured.
Second, there is jitter, the famous VoIP issue of garbled or tinny audio. When VoIP data packets are having a hard time getting through at the pace that’s needed, words will randomly cut out or there will be distortion on the line. This can make it hard to understand the other caller.
The third common issue is lost data. This comes from actual packet loss, not just delay. You know you have lost data when syllables or entire words are not just delayed, but actually missing. This disrupts a call even more than jitter.
Most VoIP calls are clear and don’t suffer from these issues, especially if there is a service-level agreement that ensures a certain measure of quality. VoIP can even deliver higher call quality than non-VoIP phones in many cases.
Yet, as with all calling, sometimes there are network issues. So if you are selecting a VoIP provider, or just think your existing solution is not up to par, check its MOS and R-Factor scores.
Edited by Rory J. Thompson