Handling mobility in IoT applications using the MQTT protocol

Connectivity clearly plays an important role in Internet of Things (IoT) solutions, and the efficient handling of mobility is crucial for the overall performance of IoT applications. Currently, the most widely adopted protocols for IoT and Machine to Machine (M2M) environments, namely MQTT, CoAP or LWM2M, are directly dependent on the TCP/IP protocol suite. This suite is highly reliable when using wired networks, but it is not the best solution in the presence of intermittent connections. In this work we provide a solution to improve MQTT with an emphasis on mobile scenarios. The advantage of the solution we propose is making the system more immune to changes in the point of attachment of mobile devices. This way we avoid IoT service developers having to explicitly consider this issue. Moreover, our solution does not need extra support from the network through protocols like MobileIP or LISP. The obtained results show that our proposal, based on intermediate buffering, guarantees that there is no information loss during hand-off periods due to node mobility; furthermore, based on discrete event simulation results, we determine the maximum number of sources and the required amount of buffers for a mobile node.