🕐

TCP Pacing & TSQ: Eliminating Bufferbloat

Simple

Free preview · 2 of 5 steps

Bufferbloat: why fast connections feel laggy

A 100Mbps fiber connection should have ~5ms latency. But during a file download, your video call stutters and games spike to 200ms. This is bufferbloat: TCP's burst-based sending fills up queue buffers in routers, cable modems, and NICs — creating 100–500ms of artificial delay for every other flow.

The root cause: TCP sends up to cwnd (congestion window) worth of data as a single burst, then waits for ACKs. This burst fills available buffers, and every other flow's packets must wait behind it. TCP Pacing and Fair Queuing are the solution.

Packets in motion — click to inspect:

1 / 2

Space to play/pause · ← → to step