What is MQTT? What you need to know

Message Queuing telemetry transport or simply MQTT is a simple lightweight protocol for transmitting data between machines and has become one of the most important protocols in the Internet of Things before we get into the technical aspects let's take a quick look at the history of MQTT it was developed in 1999 by IBM as a lightweight protocol with low bandwidth and power requirements it was intended to transfer monitoring data from an oil pipeline by an extremely expensive satellite link fast forward in 2014 it was approved as a standard by the organization of the advancement of structured information standards or in short and I prefer this oasis in 2016 it was approved as an ISO standard so how does it work together a basic understanding of MQTT we need to take a look at the following points the broker publishing and subscribing topics and quality of service as a bonus we also have a real-life example for you at the end of the video so stay tuned so the broker all devices or clients communicate through a middleman this is a server or a broker in MQTT terms the broker can be installed on your PC Mac most Linux systems including raspbian on the Raspberry Pi in container installations or in the cloud actually there are already many cloud MQTT services available two of the most popular brokers are hive MQ and mosquito a free open-source broker which we have already used multiple times in previous maker Monday episodes so check those out publishing and subscribing client devices transfer or receive information either from the broker or by subscribing to specific topics they can also publish messages of a specific topic to the broker one client does not stay in direct contact with another client the whole time since any connection goes through the broker also a client is not limited to just publishing or subscribing all kinds of devices can access clients such as micro controllers like Arduinos or ESP s as well as computers topics topics are a way of categorizing the kind of messages that might be sent clients can transmit messages of a specific topic and can also subscribe to specific topics the broker gets all messages and then forwards the messages to all clients that are subscribed to that topic topics are basically high keek all categories if you want a device to get messages from multiple topics you can use wildcards single level wildcards are indicated with a plus icon which replaces one topic level for example the room level then you will get all temperature data from any room on the third floor multi level wildcards are indicated with a hashtag and that replaces any deeper topic level from the wildcard onwards so now you get all data from the third floor if there are no subscribers to a topic at all the broker discards the message but the publisher can also tell the broker to keep the message until a client subscribes to the topic that makes sense if you want a new client to get the latest value right when it subscribes quality of service QoS depending on your needs for a message being definitely received or definitely received just once there are three different types of QoS settings available for messages you send QoS 0 or fire-and-forget that's the lightest one when it comes to network usage the message is sent once regardless of any feedback from the broker QoS 1 the publisher will send its message over and over again until it gets a confirmation message from the broker this can lead to multiple deliveries QoS 2 is a four-part handshake this guarantees that each message is received only once by confirming their seat back and forth because MQTT is so lightweight in terms of data size and processing power it is available to a vast majority of machines even with very low resources just as a footnote data sizes can be as small as 2 bytes but can also contain up to 256 megabytes mqtt transmits its data mainly through the tcp/ip protocol a variation of mqtt is mqtt SN which opens the protocol to even more devices it is aimed towards non tcp/ip networks such as Bluetooth or ZigBee therefore it is a very important tool in the IOT world if you are interested in a real life scenario Greg a colleague of ours uses MQTT to unlock his front door if he forgets his keys inside the house if you want to know how to pull that off check the make a Monday episode with him for more maker Monday basics consider subscribing below and show us some love you [Music]

Channel: PaesslerAG

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Id: QSwR-JMmNOo

Length: 4min 36sec (276 seconds)

Published: Mon Nov 04 2019