Bufferbloat: Why the Internet Lags When Someone Uploads

A speed test measures how much data moves. It does not measure how long a small, urgent packet waits behind a big one. When the wait gets long, a video call stutters while the speed test still says the line is fast. That wait has a name. This guide explains what it is, how to test for it at home, and what the fix looks like.

What is going on inside the box?

Every piece of network gear has a queue, a waiting line for packets. A queue is useful: it smooths out bursts. If the queue is too long, a packet that arrives behind a pile of others waits its turn, and the delay can be large. Your connection feels like a single grocery lane where one quart of milk waits behind a full cart.

The Bufferbloat project calls the problem “the undesirable latency that comes from a router or other network equipment buffering too much data,” and says it is “relatively easy to fix.” Where it hurts most is the narrowest point on the path, which is often the router or the radio link, and most often when uploading.

How do you test for it?

Run a speed test that reports latency under load. Waveform offers a bufferbloat test on its website. Or measure by hand: start a continuous ping to a well-known address (the ping test article shows how), note the typical time, then start a large upload from another device and watch the number. If it climbs sharply and stays there, you have bufferbloat somewhere on your side of the line.

The FCC's Measuring Broadband America program measures the same thing. Its Thirteenth Report gives latency under load, which it calls working latency, and says results under load are higher than idle results (data from September and October 2022). Seeing some rise is normal; a very large one is the sign.

What fixes it?

The usual fix is smarter queue management on the router. RFC 8290 describes FQ-CoDel, a scheduler and queue manager that “mixes packets from multiple flows and reduces the impact of head-of-line blocking from bursty traffic,” and “provides isolation for low-rate traffic such as DNS, web, and videoconferencing traffic” by keeping queue lengths short. Many modern routers offer it under names such as smart queue, SQM, adaptive QoS or traffic shaping.

Turn it on, and set the speed limit slightly below your real upload and download speeds, so the queue forms in the router where it is managed rather than somewhere you cannot see. Then retest. Our QoS guide covers the related setting that favors a device or an app.

What can you do without a new router?

Behavior helps. Schedule large uploads, such as cloud backups and photo syncs, for the night; the data guide shows how. Pause a game download when a call starts. Put the work laptop on a cable. If you run cameras that upload constantly, look at their quality setting, since a lower setting sends less (see camera upload use).

Not every case is bufferbloat. Weak Wi-Fi, a busy wireless link or a distant tower can add delay too, and the latency guide explains the difference.

What can High Desert say?

High Desert publishes plan speeds, listed as up to 500, up to 800 and up to 1 Gig down with up to 200 Mbps up, and it does not publish a latency figure. If your tests show long delays only when the line is busy, call 775-575-9593 any day from 9 to 5 with your results, noting the time and what else was running.

Before you choose a provider, send your address through the check form; a person checks the path from the nearest tower and calls with the answer.