Latency can be measured in both directions and is quantified in terms of milliseconds (ms). Latency is measured in two ways:
- One-way latency is the time it takes for a data packet to travel in one direction, and it is generally used to diagnose network problems.
- Two-way latency, also known as ‘round trip latency’, measures the round trip time, and this figure is used to calculate MOS (mean opinion scores).
When testing Latency for our customers, Spearline performs Two-way latency tests!
International Telecoms Union (ITU) recommendations.
The ITU of the United Nations recommends (ITU-T G.114) no more than 150ms latency (one-way) for voice calls. Beyond 150ms (300ms round trip), call quality declines to the point of unacceptable and completely non-productive.
- A one-way call latency of 20 ms is normal.
- A call latency of 150 ms is barely perceptible and thus acceptable.
- If call latency is above 150 ms then the quality and consistency of the call begins to decline.
- A latency of 300 ms or greater is utterly unacceptable.