Quality of service, or QoS, describes the performance characteristics of a network service, especially latency, reliability, jitter, and throughput. In mobile and enterprise networks, QoS settings decide which traffic gets priority when resources are limited, helping voice, video, and critical control traffic stay usable under load.
QoS matters in cyber security because availability is a security property, not just an engineering metric. Attackers often try to overwhelm networks with denial-of-service traffic, creating congestion that raises latency and drops packets. Defenders respond with traffic shaping, rate limiting, segmentation, and priority rules to protect essential services. In telecom environments, QoS also helps operators prove that modernization, spectrum changes, or core-network upgrades do not weaken user experience or operational resilience.