Synchronising two or more MQTT brokers


I was wondering how to synchronise multiple MQTT brokers when using the MQTT Distribution module?

Let’s use the Purdue Model to explain a scenario.

If I have an Ignition Gateway running all my SCADA in Layer 3. Here everything is connected via OPC UA. Then in Layer 3.5 I have a DMZ with an Ignition Gateway with the MQTT Distribution module installed. From Layer 3 to Layer 3.5 I use the Transmission Module to publish my tags to the Distributor. In Layer 4 I have an additional Ignition Gateway which also has an MQTT Distributor module installed.
How would I then synchronise the namespace from the MQTT Broker in Layer 3.5 to the MQTT Broker in Layer 4? Would I need to install both MQTT Engine and MQTT Transmission in Layer 3.5 to subscribe to the local MQTT Broker and publish the tags to the MQTT Broker in Layer 4? To me that sounds like a bit of an overkill…

I have seen that other MQTT Brokers support Bridging between two MQTT Brokers. Is that an option with MQTT Distributor Module?

Currently MQTT Distributor and Chariot do not support bridging. Bridging will be supported in the next release of Chariot.

So for the time being, installing Engine and Transmission at layer 3.5 is the way to do it. We have a number of customers doing exactly this today.

Hi Wes,

Thank you for the answer. What is the timeline of the next release of Chariot?

We are aiming to get the next release of Chariot out soon in Q1, but do not have a hard date yet.