Performance Evaluation of the CoAP Protocol with Security Support for IoT Environments

Internet of Things (IoT) can be defined as the interconnection through Internet of an unprecedented number of devices with the purpose of exchanging data. It stands as one of the most popular technologies for the following years and it is requiring substantial changes in the Internet protocols to meet its requirements. As the application layer is decisive for the quality of the connection, this paper analyzes the performance offered by one of the most popular protocols for the application layer in IoT: the Constrained Application Protocol (CoAP). This analysis aims to examine the features and capabilities of this protocol and to determine its feasibility to operate under constrained devices using security support. For this, a realistic network scenario is deployed to run the simulations and to measure bandwidth, consumption of resources (i.e., CPU cycles and bandwidth usage) and communication latency. Additionally, the trade-off between security and performance is discussed measuring the bandwidth overhead and the consumption increase associated to secure the communications. Different ciphering and authentication algorithms are tested, following the recommendations made by the Internet Engineering Task Force (IETF).