SCoAP: An integration of CoAP protocol with web-based application

Abstract

This paper proposes an interesting yet practical use case of CoAP, an important application protocol in realizing the Internet of Things (IoT) vision. Originally, CoAP protocol is designed to communicate between embedded devices, however its applications can spread well over the Internet by exposing the devices' capabilities to the Web as Web resources. Thus, we claim that CoAP protocol could also be used in web-based application to leverage CoAP-based resources. Unfortunately, the design of CoAP protocol, for example, bind to UDP socket to reduce the package size or bidirectional communication to cope with duty-cycle power scheme, prevents it from being supported on conventional web browsers. Additionally, translation of CoAP into HTTP protocol via HTTP/CoAP proxy as recommended by IETF is not the best solution since many CoAP features are limited. Instead, new bidirectional web protocol such as HTML5 Web Socket would help to preserve the protocol's characteristics. We propose a solution called SCoAP that facilitates true CoAP communication in conventional web browsers by applying HTML5 Web Socket protocol. Experiment results have shown significant advantages of SCoAP solution over standard HTTP/CoAP proxy in term of network traffic and computational demand.