What Can I Do About Bufferbloat?

Bufferbloat is high latency (or lag) that occurs when there’s other traffic on your network. This means that your network isn’t responsive under normal working conditions. It’s wasting your time.

How does bufferbloat apply to me?

Watch the Bufferbloat Video which presents an intuitive description of of Bufferbloat. Or read the somewhat more detailed Best Bufferbloat Analogy - Ever blog post.

Most important - How do I get rid of Bufferbloat?

1. Measure the Bufferbloat: Use the Waveform Bufferbloat Test or Speedtest.net) to measure the latency under load. If Waveform shows a letter grade worse than a B, or if Speedtest.net shows more than 75 msec in either download or upload, you probably have bufferbloat. Some device at your bottleneck link (usually your router) is letting bulk traffic (uploads/downloads) interfere with (and delay) your time-sensitive traffic (gaming, video calls, Facetime, etc.) For more details about testing, read the Tests for Bufferbloat page.

2. Possible Solutions: There are lots of ways to throw time or money at this problem. Most won’t work.

  • Your ISP would love to sell you a faster connection, but link speed isn’t the problem - it’s your router buffering more data than necessary.
  • Buying an expensive router (even one for “gaming”) won’t necessarily help, since many commercial, off-the-shelf router manufacturers are clueless about Bufferbloat.
  • Twiddling the router’s QoS might make a difference, but it’s a hassle, and only helps a bit.
  • Instead…

3. Take Control of Your Network: No one else (not your router manufacturer, nor your ISP) has a strong incentive to fix Bufferbloat. But once you take control, the network will stay fixed for all time, and you can adapt to changing practices at your ISP or other vendors.

You need to find a router vendor that “understands” latency/responsiveness/bufferbloat, and has firmware that uses one of the Smart Queue Management algorithms such as cake, fq_codel, PIE, or others. Here are some options, from easy to harder:

  • Enable SQM settings if your router already has them.

    First, measure the link speed without SQM using Waveform or Speedtest.net. Each of these is good because they display latency when the line is idle and when there’s upload or download traffic. Then turn on SQM, setting the up and down speed to the measured values above. Keep running your speed test and adjusting the SQM speed settings until the latency remains low while achieving good speeds. See, for example, this description of a tuning session.

  • Install an off-the-shelf router with SQM Several commercial router vendors have a clue. Here is a list of those we have found:

  • Upgrade your current router. Install OpenWrt firmware (version 22.03 or newer). The Smart Queue Management guide tells how to configure the luci-app-sqm package. Or install suitable DD-WRT, Gargoyle or Tomato firmware, all of which support some kind of queue management based on FQ-CoDel and/or Cake.

  • Call your router vendor’s support line if none of the above are possible. You have the information from the latency tests. Mention that the ping times get really high when someone is up/downloading files, and that it really hurts your network performance. Ask if they’re working on the problem. Ask when they’re going to release a firmware update that solves it.

Your network’s responsiveness is in your hands…

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Recent Updates

Oct 20, 2023 Wiki page
What Can I Do About Bufferbloat?
Dec 3, 2022 Wiki page
Codel Wiki
Jun 11, 2022 Wiki page
More about Bufferbloat
Jun 11, 2022 Wiki page
Tests for Bufferbloat
Dec 7, 2021 Wiki page
Getting SQM Running Right

Find us elsewhere

Bufferbloat Mailing Lists
#bufferbloat on Twitter
Google+ group
Archived Bufferbloat pages from the Wayback Machine

Sponsors

Comcast Research Innovation Fund
Nlnet Foundation
Shuttleworth Foundation
GoFundMe

Bufferbloat Related Projects

OpenWrt Project
Congestion Control Blog
Flent Network Test Suite
Sqm-Scripts
The Cake shaper
AQMs in BSD
IETF AQM WG
CeroWrt (where it all started)

Network Performance Related Resources


Jim Gettys' Blog - The chairman of the Fjord
Toke's Blog - Karlstad University's work on bloat
Voip Users Conference - Weekly Videoconference mostly about voip
Candelatech - A wifi testing company that "gets it".