  MQTT (Message Queuing Telemetry Transport) has become the perfect messaging
protocol for IoT (Internet of Things) systems since it is the lightest protocol
designed for low bandwidth, high-latency, unreliable networks. Today, the
strategy of distributing several MQTT brokers on the networks is widely used
because the strategy of using a single broker is no longer efficient. However,
in the distributing architectures of MQTT brokers, a subscriber should have
prior knowledge about the address of the broker that publishes the data on the
topics of interest. In this paper, we tackle this challenge by proposing a
mechanism that connects the subscribers to the brokers in a transparent way.
The proposed approach, known as TD-MQTT (Transparent Distributed MQTT brokers),
requires no prior knowledge of the brokers by the subscribers. The data will be
carried automatically from brokers that can change their configuration and
location. The transparency will help to use IoT data without worrying about
their location and dynamic configuration changes. To evaluate our approach, we
compared it with the basic distributed MQTT and the EMMA (MQTT Middle-ware for
Edge Computing Applications) approach. The results of the evaluation show that
TD-MQTT is much better than the standard MQTT, especially in terms of response
time.
