Network latency is the time a packet takes to reach its destination and return, measured in milliseconds. It is separate from bandwidth. High latency makes live video lag behind reality, makes PTZ control feel unresponsive and delays alerts, even on a fast connection.
Latency comes from distance, congestion, queuing and slow devices in the path. A camera system can have plenty of spare bandwidth and still feel sluggish.
Distance and congestion
Every hop adds delay, and a satellite or cellular link adds a great deal. Congested links queue packets, so delay rises exactly when the site is busiest and the footage matters most.
Why it matters for video
Operators notice latency when a PTZ moves after they released the joystick, or when a gate opens a second late. Keeping the recorder and viewer close, and prioritizing video traffic, keeps delay predictable.
Related:Glossary: Network throughputCommercial security camera systems