Experimental evaluation of the coap, http and spdy transport services for internet of things

Abstract

Internet of Things (IoT) seeks to broaden the scope of the Internet by connecting a variety of devices that can communicate with the Internet. Transport services for IoT are crucial in enabling the applications to communicate reliably and in a timely manner while making efficient and fair use of the potentially scarce network resources. The communication with IoT devices is often implemented using HyperText Transfer Protocol (HTTP) or a specifically designed protocol such as Constrained Application Protocol (CoAP) that is a specialized web transfer protocol for constrained nodes and networks. In this paper we discuss various options for modifying or adapting HTTP to offer better transport service for IoT environments. We consider HTTP, SPDY that has been developed to speed up HTTP in general, IoT-HTTP and IoT-SPDY that are adaptations of HTTP and SPDY for IoT, and CoAP as transport services for IoT and experimentally evaluate their performance. The results of our experiments show that CoAP has the lowest object download times and the least number of bytes transferred compared to the other four transport services. IoT-HTTP and IoT-SPDY have around 50% shorter object download times and smaller number of bytes transferred compared to HTTP and SPDY.