Consistency matters
Jitter describes variation in latency from one packet or request to the next. A connection can have a reasonable average ping but still feel unstable if individual delays vary dramatically.
Why jitter matters
Real-time applications such as voice calls, video meetings, online games and remote desktops work best when packets arrive at predictable intervals. Large variation can contribute to stutter, audio gaps, rubber-banding or temporary quality reductions.
What causes jitter
Common causes include congested Wi-Fi, radio interference, overloaded routers, upstream saturation, mobile-network variation and queueing elsewhere in the network path. Short bursts of background traffic can create spikes even when the average download speed looks healthy.
How to reduce jitter
Compare Wi-Fi with Ethernet, move closer to the access point, reduce competing traffic and check whether large uploads are filling the connection. Modern routers with effective queue management can sometimes improve consistency under load.