Constrained Application Protocol for Low Power Embedded Networks: A Survey

IPv6 will make it possible to provide Internet connectivity to any object embedding a communication device. In the same line, Web technologies will make managing, communicating and visualizing any information provided by these devices attractive to the end users and application developers. Most of the new devices connected to this Web of Things (WoT) will be embedded and wirelessly connected. However, current Web technologies have been developed with powerful devices in mind not being suited for this kind of constrained environment. In order to make the WoT a reality for low power embedded networks, specialised protocols that consider the energy, memory and processing constraints of wireless embedded devices must be designed. The IETF recently created the CoRE group whose first goal has been developing a Restful application layer protocol for communications within embedded wireless networks referred to as Constrained Application Protocol (CoAP). The year 2011 has seen a big push in the research community towards evaluating the performance and features of CoAP protocol, indicating a growing interest in the community towards Restful interactions in low power wireless embedded networks. This paper analyses those recent advances to provide a clear picture on what has been achieved so far in the evaluation and development of the Constrained Application Protocol.