The Quality of Service (QoS) ensures reliable data delivery performance of any type of IoT application under resource-limited characteristics. It prioritizes the messages based on the application type and accomplishes better network performance. The selection of QoS metrics is crucial, as it decides the performance efficiency of any network. Network throughput and delay are the main QoS metrics. Some of the QoS measurement concerns are bandwidth, latency, error rate, and delay jitter. For instance, the video conferencing applications of IoT necessitate maximum bandwidths and minimum delay to enhance performance efficiency.
   The QoS protocols efficiently handle the message queuing and allocate sufficient bandwidth to the specific applications. The queuing management models successfully deliver the packets to the desired destination by storing the traffic under high network traffic conditions. The bandwidth management schemes effectively minimize the congestion by computing and controlling the network data traffic. Some of the bandwidth management mechanisms are traffic shaping, scheduling, and rate-limiting. Moreover, the QoS plays a significant role in IoT to accomplish the desired level of performance.
   QoS in IoT communication denotes effective resource utilization and offers a reliable backbone to the IoT network. It is important to offer secure and intelligent services without increasing delay, bandwidth consumption, and packet loss by classifying the network traffic and allocating the resources effectively. In IoT, the designed protocol standard defines the QoS metrics to understand and satisfy the requirement of IoT applications by analyzing various IoT network scenarios.