What is a QoS requirement for VoIP calls?

A common and critical QoS requirement for acceptable voice quality in VoIP calls is to ensure that the one-way mouth-to-ear latency does not exceed 150 milliseconds. Latency greater than this value can lead to noticeable delays, causing speakers to talk over each other and significantly impacting the natural flow of conversation.

15% packet loss is an extremely high and unacceptable level for VoIP, as even 1% or 0.5% packet loss can lead to noticeable voice degradation and dropped words.

150 bps (bits per second) is an astronomically low and incorrect bandwidth figure for a VoIP call, which typically requires tens of kilobits per second (e.g., G.729 at 8-32 kbps, G.711 at 64-80 kbps).

150 ms of jitter is an unacceptably high level for VoIP; ideal jitter should be kept below 30 ms to prevent excessive de-jitter buffering, which adds to latency and can cause audio artifacts.