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RADIUSdesk MQTT Implementation

Introduction

MESHdesk and APdesk traditionally makes use of a heartbeat system to communicate and report to the back-end.
We now also include a MQTT based implementation to allow real-time communication between the mesh nodes or access points and the back-end.
This implementation is used as a compliment to the heartbeat system, making it more robust while offering you added real-time communication.
The MQTT implementation is not compulsory in order to have a working deployment but it does offer a lot of advantages.
It is ideal for hardware that is used in a IOT environment where you need immediate execution of commands.

Consider the following diagram and then the subsequent discussion of each of the components.

The ExtJS GUI can be used to send commands to the mesh nodes and access points managed by MESHdesk and APdesk respectively.
The communication between ExtJS and the CakePHP application consists of REST-like API calls using HTTP or HTTPS.
This means essentially that these actions can easily be automated or done with another GUI should the need arise.

If MQTT support is enabled on the system and someone initiate a command execution action from the GUI the controller code handling this request will send this request to the API Gateway.
This communication between the CakePHP controller and the API Gateway also consist of REST-like API calls using HTTP or HTTPS.

The API Gateway is a Node.js based web service that acts as a middle man.
It will
- Receive instructions from CakePHP and translate them to MQTT publish actions (Command) which are published to the Mosquitto MQTT Broker.
- Subscribe to MQTT topics (Response) on the Mosquitto MQTT Broker which will get input from the mesh nodes and access points and translate them to HTTP/HTTPS based API calls to CakePHP.

The mesh nodes and access points communicate with the CakePHP back-end using HTTP/HTTPS to fetch its configuration and do reporting.
If the system has MQTT support enabled the mesh node or access point will configure itself to publish and subscribe to certain topics on the Mosquitto MQTT Broker.
The system works on a command and response principle.
- The mesh node or access point subscribe to a topic where it will expect commands from the API Gateway.
- The mesh node or access point will publish to a topic where the API Gateway expect responses.
- The API Gateway will publish to a topic where the mesh node or access point expect commands.
- The API Gateway will subscribe to a topic where the mesh node or access points publish their responses.

There are two components of the MQTT setup that needs to be configured
- Configuration settings for mesh nodes and access points (MESHdesk and APdesk)
- Configuration settings for the MQTT API Gateway.