Coap based congestion control mechanism for low power IoT networks

Abstract

Internet of Things has billions of connected devices into internet. CoAP is a Constrained Protocol used in application layer of IoT Protocol Stack. CoAP is running on top of User Datagram Protocol (UDP), which means that, there is no possibility of congestion control in it, so CoAP is responsible for Congestion control mechanism. UDP has no knowledge on congestion control. IoT has significant resource constraint, due to this there are lots of design challenges in IoT network. This paper proposes a simple change in the CoAP protocol named CoCoA (CoAP Simple Congestion Control / Advance). CoCoA introduces novel Round Trip Time (RTT), VBF (Variable Back off Factor) and aging mechanism to calculate the dynamic and controlled Retransmission Time Out (RTO) for IoT Networks. This paper compared with the existing all the congestion control mechanism and the implementation result shows that the proposed mechanism is better than the existing mechanism in terms of throughput, power consumption, memory foot print and fairness index.