XXX-X-XXXX-XXXX-X/XX/$XX.00 ©20XX IEEE Performance Evaluation of CoAP Broker and Access Gateway Implementation on Wireless Sensor Network Aldwin Akbar Hermanudin Department of Electrical Engineering Universitas Indonesia Depok, Indonesia aldwin.akbar@ui.ac.id Fransiskus Astha Ekadiyanto Department of Electrical Engineering Universitas Indonesia Depok, Indonesia astha.ekadiyanto@ui.ac.id Riri Fitri Sari Department of Electrical Engineering Universitas Indonesia Depok, Indonesia riri@ui.ac.id Abstract—Currently there are several Application Layer protocols running on Internet of Things system. Protocols such as MQTT, CoAP, XMPP, and DDS have different architectures and performance. Wireless sensor networks operating in low power, low bandwidth and with limited reliability, is more suitable to use CoAP. However, CoAP is inferior to MQTT architecture in terms of scalability. Therefore this research focuses on CoAP Broker implementation of an IETF draft which enables MQTT-like architecture to be implemented in CoAP. This research aims to implement an Access Gateway with the proposed protocol and show its use-case in poultry farm, involving sensor monitoring and actuator controls on multiple location. The result of this research shows the success of CoAP Broker implementation along with the mentioned use-case and the performance evaluation which has not indicate any congestion when handling 130 requests per second and good error-rate with low value between 0.01% - 0.04%. Keywords—MQTT, CoAP, CoAP Broker, Internet of Things, wireless sensor network, sensor I. INTRODUCTION In recent years, the use of Internet of Things has grown rapidly, with the evidence of usage in industry, housing, and security sector. This led to an increase in the production of devices that utilize Internet of Things architecture. According to Gartner, an analyst company, by 2020 there will be 26 billion objects connected to the Internet [1]. The development of Internet of Things, has been supported by Wireless Sensor Networks technology. Wireless Sensor Network itself is a network of sensors connected to each other wirelessly. Wireless sensor networks may consist of nodes that have limited resources, limited processing capabilities, and unreliable data transfer between nodes [2]. There are two commonly used protocols in an Internet of Things system namely MQTT and CoAP. Compare to CoAP, MQTT is good protocol in terms of scalability, but poor on bandwidth usage. Whereas CoAP has a good bandwidth usage but limited on its scalability. MQTT with its publish-subscribe architecture allows each node to perform many-to- many communication through a certain topic of interest. Whereas CoAP, that uses request-response architecture, can only perform one-to-one communication. Therefore, to create a network with vast number of sensor, a couple of strategy is available. One way is to utilize current protocol and develop new feature that can overcome its current limitations. Another way is to design a good topology and infrastructure to support scalability between sensor/actuator nodes. This paper aims to do both by developing CoAP that utilize publish-subscribe architecture defined in an IETF draft on a wireless sensor network with the usage of hierarchical topology. The result is obtain by running experiments involving multiple sensor and actuator simulating a poultry farm with multiple location. Even though, the process of data transfer in this paper CoAP’s publish-subscribe architecture is based on an existing library, a novel contributions that this paper give is the use of hierarchical topology, the development of MQTT to CoAP bridge, and the implementation of CoAP’s publish-subscribe architecture. The organization of this paper is as follows: Section II explains the MQTT and CoAP protocols. Section III proposed a novel design of Access Gateway with CoAP Broker. Section IV gives further detail of the Access Gateway Design. Section V defines the experiment setup and scenario. Evaluation of the proposed Access Gateway and network architecture is explained in Section VI. Section VII gives the conclusion and future works. II. APPLICATION LAYER PROTOCOL A. Message Queue Telemetry Transport Message Queue Telemetry Transport (MQTT) is a binary protocol that resides in the application layer. MQTT is designed to be a lightweight protocol, has small overhead and small code footprint [4].