[nvarsj]

It’s when you’re gaming and your ping jumps to 500 because someone is watching Netflix. It’s one of the main flaws in the currently deployed internet for end users. There are a lot of novel solutions (codel and so on) - but still not widely deployed.

More generally it refers to any hardware/system with large buffers - needed to handle large throughput but can lead to poor latency due to head of queue blocking.