Latency

Latency (also called delay) is the time it takes for a voice packet to travel from the sender to the receiver. In VoIP, latency is typically measured as one-way delay. Calls feel natural when one-way latency stays below 150 ms; above 300 ms, conversations become noticeably awkward.

Sources include network propagation delay, codec processing time, jitter buffer delay, and queuing delays in routers. Geographic distance, congested links, and poorly configured QoS policies all contribute.