Experiments with COAP over L2 technologies

Abstract

In a world where the Internet of Things (IoT) becomes more and more popular, there is always a need for more targeted ways for constrained devices to communicate. The Constrained Application Protocol (COAP) was designed for that purpose, targeting small, low-power sensors, switches, valves and similar components that need to be controlled or supervised remotely, through standard Internet networks. It was designed by The Internet Engineering Task Force (IETF) Constrained RESTful environments (CoRE) Working Group with the following features in mind: Overhead and parsing complexity, URI and content-type support, Support for the discovery of resources provided by known CoAP services, Simple subscription for a resource, and resulting push notifications and Simple caching based on max-age. Although COAP can in principle be implemented over any type of network technology ensuring end-to-end connectivity, it is usually implemented on top of UDP, which means it also requires IP to be implemented underneath. In this thesis, we have implemented an experiment where a COAP packet is created and injected directly over a Layer 2 technology (Ethernet). The packet is received by a Raspberry Pi in order to be decoded and for some predefined operations to be performed, based on the packet's payload.