The large amount of data collected in the Internet of Things (IoT) need to be transmitted to servers for processing in order to provide various services. Due to the limited amount of resources in IoT, including network bandwidth, node processing abilities, and server capacities, congestion control in IoT plays a crucial role for meeting service performance requirements. In this paper, we propose a model for congestion control in IoT with an improved Random Early Discard (IRED) algorithm. We employ queueing theory to analyze the performance of the proposed control mechanism. We also conduct extensive simulations to evaluate performance of the proposed control and compare it with regular RED algorithm. Our analysis and simulation results show that the proposed control achieves comparable delay performance and better throughput performance compared to standard RED. The simple control mechanism of IRED makes it more suitable to be implemented in IoT.