QoS in LAN & WAN Environments refers to the implementation of Quality of Service techniques across both local area networks and wide area networks to manage and prioritize network traffic efficiently. It ensures that critical applications such as voice, video, cloud services, and business applications receive higher priority than regular data traffic. In LAN environments, QoS improves communication within offices, campuses, and enterprise buildings. In WAN environments, it optimizes traffic across remote offices and geographically distributed locations. Network administrators use techniques such as traffic classification, marking, queuing, shaping, policing, and bandwidth allocation to improve network performance. These methods help reduce latency, jitter, packet loss, and network congestion. QoS in LAN & WAN Environments improves communication quality, network reliability, and overall user experience in enterprise infrastructures.