Architecture

As shown in above picture, the modules of the bridge are:

• ConnectionManager: manage the connections between the client and bridge
• Protocol Converter: translate the MQTT protocol packets to Bridge internal Message
• Downstream Module:
  • receive messages from client
  • handle the SUBSCRIBING requests
  • push messages to CLIENTS according to TOPIC
  • forward messages to other BRIDGES if necessary
• Message Store:
  • persistent MESSAGES which needs to be retained
  • query OFFLINE messages for any one client
  • query message by MessageId
• Subscription Store:
  • query SUBSCRIBED clients by TOPIC
  • maintain the mapping from TOPIC to CLIENTS