Quality of Service, the toolkit for keeping latency-sensitive traffic flowing predictably across crowded networks. Articles tagged QoS cover classification and marking (DSCP, CoS), MQC, queueing (LLQ, CBWFQ), policing, shaping, and voice and video treatment in SD-WAN and wireless.
Without proper QoS, wireless becomes best-effort and business traffic suffers. A Cisco C9800 QoS guide covering 802.11e, DSCP mapping, Auto QoS profiles, and wireless policies for voice, video, and critical apps.
Voice VLANs let a single access port carry both data traffic from a PC and voice traffic from an IP phone — each in its own VLAN with its own QoS treatment.