Jitter

What is jitter?

Data travels in small packets. On a steady link each packet takes about the same time. On an uneven link some come quickly and some late. The IETF's RFC 3550, which defines the Real-time Transport Protocol used for voice and video, describes interarrival jitter as a statistical measure of this variance in packet spacing. Apps smooth it with a short buffer, and when jitter is bigger than the buffer, you hear gaps and robotic voices or see video freeze.

Jitter is written in milliseconds, like latency, but they are different measures. Latency is how long. Jitter is how much that changes.

Why does it matter on a wireless link?

Radio paths share the air. Rain or snow, a swaying branch, a busy evening and noise from other radios can all make delivery less even. Inside the house, Wi-Fi is often the larger source: walls, a microwave oven, a crowded 2.4 GHz band and distance from the router all add variation before the signal ever reaches the antenna on your roof.

Calls, video meetings, remote desktop and online games react to jitter first. Downloads and streaming video buffer ahead and mostly hide it.

What should I do about it?

Compare a wired test with a Wi-Fi test. If the wired line is steady and Wi-Fi is not, fix the Wi-Fi: move the router, use the 5 GHz band for the device (see Wi-Fi bands), or run a cable to the device that matters. Our guide on why video calls freeze has the checklist.

If a wired test also shows wide swings, note the time of day and call 775-575-9593. A technician can look at the radio path. Do not climb to the roof or touch the outdoor radio. You can also try a feature called QoS on your router, covered in QoS, which puts calls ahead of bulk traffic.