Quality of Service for Key Traffic

Quality of Service (QoS) is a set of techniques that prioritize certain traffic over others on a busy network. Not all traffic is equal: a voice call needs to arrive instantly and steadily, while a large file download can wait a moment. QoS ensures important, time-sensitive traffic gets the bandwidth and low delay it needs, even under congestion.

When a link fills up, packets queue and some are dropped. For a file transfer this just means a brief slowdown, but for real-time traffic like voice and video it causes choppy audio, frozen video, and dropped calls. QoS exists precisely to protect these sensitive flows so they keep working when bandwidth is scarce.