What is buffer bloat?
Buffer bloat is a networking issue where the memory (buffer) of a device fills up before it sends out data. Devices with less buffer memory are often better at maintaining performance because data doesn’t sit in the queue as long.
To an end user, this can look like a connection that starts fast but can’t sustain that speed once the RAM buffer is depleted. It also affects latency, which directly impacts user experience.
How can end users test for buffer bloat?
There are online tools that measure buffer bloat. A good example is:
👉 https://www.waveform.com/tools/bufferbloat
These tools measure how much your latency increases or decreases under load—commonly called LUL (Latency Under Load). In short, it shows how much your connection fluctuates during downloads or uploads.
What does this look like in the real world?
Imagine a user with two internet connections: one over a wireless link, and another over a fiber link. Both are capped at 100 Mbps.
Even though both connections show the same speed on speedtest.net, the fiber connection will finish a large download first because its latency stays stable. Speed tests don’t show latency or jitter, which can be just as important as raw bandwidth—especially for low-latency activities like video calls and gaming.
On wireless connections, buffer bloat can be a major bottleneck even if your speed looks fine.
How do we overcome this?
To reduce buffer bloat, we need to understand what causes it. It occurs when a networking device fills its buffer memory before sending data. On top of that, when a connection pushes data as fast as possible, it creates additional buffer bloat.
This is where technologies like traffic shaping and QoS (Quality of Service) come in. By deliberately capping bandwidth slightly below the maximum, they can keep latency stable and improve real-world performance rather than just chasing maximum speed.
Wrapping up
Buffer bloat is a lesser-known networking issue that can make a huge difference—especially on wireless connections.
💬 Feel free to share your thoughts or experiences with buffer bloat in the comments below!
