QoS, or Quality of Service, is a research area that focuses on ensuring that network services and applications meet the required performance standards in terms of reliability, responsiveness, and availability. This involves managing network resources, such as bandwidth and latency, to prioritize the delivery of critical data and applications over less important traffic. QoS research aims to improve the overall user experience by providing a smooth and consistent network performance for different types of data and applications. Techniques such as traffic shaping, packet scheduling, and network congestion control are commonly studied in the field of QoS.