Work out buffer size requirement instantly with clear inputs, formula shown and shareable results.
The classic rule sized router buffers at one bandwidth-delay product so a single TCP flow could keep the link full. The Stanford result showed that with N independent flows, BDP divided by sqrt(N) suffices, because their sawtooths desynchronise. Oversized buffers cause bufferbloat: the link stays full but queueing delay grows to hundreds of milliseconds.
Buffer sizing
BDP = link rate x RTT / 8; Stanford rule = BDP / sqrt(flows); drain time = buffer bits / link rate
Excessive buffering that keeps a link busy at the cost of latency. Interactive traffic queues behind bulk transfers, so video calls stutter while a download runs.
Active queue management such as CoDel or FQ-CoDel, which drop or mark packets based on how long they have been queued rather than on queue length.