A Systematic Survey on Congestion Mechanisms of CoAP Based Internet of Things

An IoT is a ubiquitous intelligent technology that enables interaction among intelligent devices via Internet. It consists of the lossy and low powered networks (LLN) connected sensors having limited power and bandwidth. For the messaging protocol, IFTF has standardized with a lightweight RESTful application layer protocol known as CoAP. It runs on the unreliable UDP layer for communication, reliability and congestion control. With the increase in no of transmissions, congestion in the network increases and it becomes difficult to overcome it using the conventional CoAP mechanism. Therefore, a new paradigm has been approached for the advancement known as CoAP congestion Control Mechanism (CoCoA). In this paper, there is a systematic survey of the traditional CoAP along with the new paradigm approaches and their algorithms is discussed. Also, a brief introduction of its working, limitations and evaluation parameters such as throughput, latency, and re-transmission are taken into consideration for survey.