A Cross-Protocol Proxy for Sensor Networks Based on CoAP

Smart technologies able to support people during their daily life, such as those linked to the Ambient Assisted Living (AAL) world, are gaining importance in today's context. In this regard, solutions to problems arising from the need to connect constrained networks with the internet are essential. In fact, constrained network, being a particular wireless network made of devices that have limited computational power and limited storage capacity, strongly differ from the internet network. Communication protocols try to overcome the issues related to the interconnection of smart devices in our smart world with the internet. A lot of efforts have been made in this direction, ending up with the creation of several different protocols and among them, in the applications context, the CoAP (Constrained Application Protocol) one is becoming increasingly relevant. The emergence of new protocols forces the need for developing proxying systems able to intermediate between the two kind of networks and to translate between the relative protocols. In this paper we are going to present a cross-protocol proxy able to broker among the HTTP, MQTT and CoAP protocols and also able to implement the caching function, that as we will deepen, is an essential contributor for the timeliness of communications. The proposed cross-protocol proxy has been tested under four operating conditions, in terms of Throughput and Round Trip Time. The results show excellent performances for both metrics taken into account, especially when the caching feature is enabled.