MQTT-ST is a MQTT broker which is able to create a distribute architecture of brokers, organized thorugh a spanning tree. It is based on the open source Mosquitto broker implementation. Our version adds a feature for interconnecting MQTT brokers automatically in a loop-free topology. Other Mosquitto features remain inalterated.
See the following links for more information on MQTT-ST:
- Arxiv paper: https://arxiv.org/pdf/1911.07622.pdf
- Source code Mosquitto repository: https://github.com/eclipse/mosquitto
- Source code repository: https://github.com/edoardesd/mosquitto
Creator information is available at the following locations:
- Research group webpage: http://www.antlab.polimi.it
- Developer github: https://github.com/edoardesd
Installing MQTT-ST is as installing Mosquitto. See the official documentation at https://mosquitto.org/download/ for details on installing binaries for various platforms.
Also the quick start for a single broker is the same as Mosquitto. More information at: https://github.com/eclipse/mosquitto#quick-start.
If you want to create a cluster of brokers, each broker must be spawned manually with a valid configuration file, i.e. mosquitto -c mosquitto.conf
MQTT-ST provides a mechanism for interconnecting automatically Mosquitto brokers in a loop free fashion. It is based on the bridging feature provided by Mosquitto (https://mosquitto.org/man/mosquitto-conf-5.html).
The bridges are created through the mosquitto.conf file. Every broker in the cluster must have a valid configuration file. The file includes a valid bridge to all the others brokers in the cluster. It consists in:
- arbitrary connection name
- broker destination address
- broker destination port (if different to the default port 1883)
- topic included in the cluster
- topic forwarding option: it must be
outfor ensuring the correct behaviour. See https://mosquitto.org/man/mosquitto-conf-5.html for more details - QoS option: high QoS is suggested
- remote broker id: anyone
Here we show an example of a cluster composed by MQTT-ST brokers. For the sake of simplicity, only 3 brokers are used: A, B and C. However, MQTT-ST can support as many brokers as your machine can start.
Every broker in the cluster must be bridged to every one else. Each broker has a different .conf file containing bridges towards all the others brokers.
For instance, broker A configuration file:
connection AtoB
address 192.168.1.3:1883
topic # out 2
remote_clientid AtoB
connection AtoC
address 192.168.1.4:1883
topic # out 2
remote_clientid AtoC
Broker C configuration file:
connection BtoA
address 192.168.1.2:1883
topic # out 2
remote_clientid BtoA
connection BtoC
address 192.168.1.4:1883
topic # out 2
remote_clientid BtoC
And so on...
- Develop a script which creates valid configuration files
- Automatic discovery of MQTT-SN brokers
- Create a tree for each topic in the syste