MQTT is a protocol created by IBM and is at alphaworks.
To send a message, a client “publishes” it to the message broker.
The message broker delivers it to the correct client(s).
Publishing a message needs two things.
And a topic.
A client identifies what messages it wants to receive by “subscribing” to a topic.
If another client publishes an update with information about the arrival time of a different flight â€“ our client will not get it.
We will only get messages published – in this case – with updates about flight 1024.
You don’t have to be so specific.
I gave an example of subscribing using wildcards.
Or it could subscribe to receive any flight time updates for Heathrow â€“ arrivals or departures, for any airline, for any flight number.
I think I may have been labouring the idea by this point!
Payload : the data you want to send
For example, recalling the sample topic structure from my last slide, a client can subscribe to get updates about the arrival time of a specific flight flying into Heathrow.
Wildcards are supported – either for a specific level of the topic tree structure, or for a whole subtree.
For example, again referring back to the sample topic structure I showed, a client can subscribe to get updates about the arrival time of any flight for any airline coming into Heathrow
The first “+” is a wildcard for the airline name, and the second “+” is a wildcard for the flight number.