QoS

Quality of Service (QoS) refers to the set of technologies and policies that manage network traffic to ensure certain types of data — particularly real-time voice and video — receive priority treatment. Without QoS, VoIP packets compete with all other traffic, leading to jitter, latency, and packet loss.

Common QoS techniques include DSCP (Differentiated Services Code Point) marking, traffic shaping, priority queuing, and bandwidth reservation. In enterprise networks, QoS policies are typically configured on routers and switches to prioritize RTP media streams.

On mobile networks, QoS is harder to control since the carrier manages the radio link. Softphone apps compensate with adaptive codecs, jitter buffers, and packet loss concealment algorithms.