Put simply, the Mean Opinion Score (MOS) is a way of ranking the voice quality of a call. MOS has been used for decades in telco networks, and traditionally has been a subjective measurement. Listeners sit in a “quiet room” and score call quality on a scale from 1 (worst) to 5 (best). The average or the arithmetic mean of all the individual scores is called MOS.
The days of solely focusing on the control plane are gone. Properly establishing and closing a call remains important. But nowadays, voice travels packet-by-packet through “bursty” IP environments – with congestion, delay and packet loss on the agenda. What is happening on the media plane becomes more and more important.
Consequently, the need has risen to evaluate not only one call by one person, but to automatically measure real-time traffic through entire networks with millions of customers.
In 2007, Voipfuture was the first to introduce a technology to directly monitor the Real-time Transfer Protocol (RTP) which is used to transport voice in IP networks.