Research on NAT Traversal Communication based on MQTT

Abstract

With the increasing numbers of clients connected to the Internet, the IPv4 address pool is nearly saturated. The industry introduces solutions of using IPv4/IPv6 dual-stack connection or NAT to mitigate the saturation. Nevertheless, these resolutions either create security issues or compromise the end-to-end communication ability. Our paper conducts research on end-to-end communication under NAT based on the MQTT protocol by subscribing and publishing messages to a particular topic. We propose a network architecture that utilizes a broker to relay the client's and the server's message, design the software implementation, and attach a sequence number into the payload of messages to resolve the shifting in MQTT's asynchronous transmission. We also evaluate the MQTT protocol's performance in variant QoS settings compared with widely used HTTP and analyze the network traffic using Wireshark, demonstrating that MQTT outperforms HTTP in 4G cellular networks. However, the developer should be aware of the lack of mature frameworks such as Django, and further research needs to be conducted.