MQTT is now officially a standard. This slide deck shows why the Internet of Things is special and why MQTT is one solution to communication between devices. There are a lot of Java code sample for getting started quickly.

1. MQTT 101
- Getting started with the lightweight IoT Protocol
Christian Götz, dc-square

2. Internet of Things

3. Internet of Things

4. Internet of Things

5. https://www.youtube.com/watch?v=iDbyYGrswtg
(00:00 - 00:44)

6. SMALL ?

7. Yep, it WAS small

8. Now it’s big ;)

9. Connection ?

10. Was Only via Wires

11. Now it’s wireless

12. For who ?

13. Was Only for Scientists

14. Now it’s for everybody

16. http://www.cs.uregina.ca/Links/class-info/215/deng_webpage/Picts/Request_Response.gif

17. Internet of Things

18. THINGS?

24. Open Hardware
Raspberry Pi is a trademark of the
Raspberry Pi Foundation

25. Screenshot from JavaOne 2013

26. Screenshot from JavaOne 2013

28. Developers
are the new King Makers
… if you don’t believe me, read this book ;)
http://thenewkingmakers.com/

29. Internet of Things

30. Things
• constrained ressources
• unreliable network connection
• no power - only battery
• “out-in-the-field”
https://flic.kr/p/dA2SMG + made transparent

31. and growing fast…

32. 2020
20,000,000,000 things
250 newbies every second
every person owns ≈ 7 devices
http://blogs.cisco.com/news/cisco-connections-counter/!
http://www.cisco.com/web/about/ac79/docs/innov/IoT_IBSG_0411FINAL.pdf

33. many sources
many targets

34. ?

35. ?

36. Things want
• Small & simple protocols
• Little overhead
• Avoid duplicate messages
• Not care about data consumers
https://flic.kr/p/dA2SMG + made transparent

37. Things love
… and others ;)

39. Subscribe

40. Publish

41. temperature
sensor
Publish/Subscribe
MQTT-Broker
laptop
mobile device
publish: “21°C“
subscribe
publish: “21°C“
subscribe
publish: “21°C“

42. subscribe At the end of the talk we
will have this working, live
temperature
sensor
MQTT-Broker
laptop
mobile device
publish: “21°C“
subscribe
publish: “21°C“
publish: “21°C“

43. MQTT Pub/Sub
• Open TCP Connection
• Binary
• Data-agnostic
• Real Push
• All “online” clients
• Topics with wildcards

44. Let’s try it out!

45. History
Arlen Nipper &
Andy Stanford-Clark
invent MQTT
royalty
free
OASIS TC
formed
MQTT
Standard
1999 2010 2013 2014

47. • Open Source
Eclipse Paho
• “Reference Implementation”
• Many languages: Java, Javascript,
Lua, C, C++, Go, Python
• Active Community
+ other clients

48. MQTT Client
• Client ID
• Know the broker (host, port)
• Can do both: subscribe & publish

49. Client Connect
MqttClient client = new MqttClient
("tcp://localhost:1883", "myclient1");
client.connect();

50. Message
• Topic
• Payload
• QoS
• Retain Flag

51. Publish Message
• Topic is for routing
• Payload is the data
• QoS is ?
• Retain Flag is ?

52. Quality of Service
QoS 0
QoS 1
QoS 2
B
B
B

53. Retained Message
• Last “Good” Value
• For each Topic
• Remove with zero byte message

54. Client Publish
String message = “Hello World!”;
client.publish("topic", message.getBytes(), 2, false);

55. Subscribe
• Topic
• QoS
• Action

56. Client Subscribe
MqttCallback mqttCallback = new MqttCallback() {
public void connectionLost(Throwable throwable) {}
public void messageArrived(String s, MqttMessage msg)
{
ACTION
}
public void deliveryComplete(IMqttDeliveryToken token) { }
};
client.setCallback(mqttCallback);
client.connect();
client.subscribe(“topic”);

57. Persistent Session
• Queue Message QoS 1 & 2
• Store subscription

58. Persistent Session
MqttConnectOptions options = new MqttConnectOptions();
options.setCleanSession(true);
client.connect(options);

59. Last Will & Testament
B
Connect
LWT
device123/status: „offline“
B
dropped
device123/status: „offline“

60. LWT
MqttConnectOptions options = new MqttConnectOptions();
options.setWill("willtopic","message".getBytes(), 2, true);
client.connect(options);

61. Heartbeat
Long TCP Timeouts
Client online ?

62. Heartbeat
MqttConnectOptions options = new MqttConnectOptions();
options.setKeepAliveInterval(1);
client.connect(options);

63. subscribe Achievement Unlocked:
temperature
sensor
Built MQTT Client
MQTT-Broker
laptop
mobile device
publish: “21°C“
subscribe
publish: “21°C“
publish: “21°C“

64. MQTT in the browser :)

65. Special Achievement:
MQTT goes browser :)

66. Brokers

67. Mosquitto
Open Source
Can run on constraint
devices
Written in C
Supports Bridging

68. HiveMQ
High performance
Open Plugin System for
Java
Native Websocket support
Clustering
Bridging Highly Scalable

69. Other Brokers
and more

70. Public Broker
www.mqttdashboard.com

71. Security

72. Securing MQTT
Protocol
Username/Password
Transport
TLS, client certificate authentication
Broker
fine-grained authentication, 3rd party integration

73. Interested in more ?

74. dc-square
Create building blocks for the IoT
Develop the Broker
Custom Plugin Development
Consulting for MQTT & IoT
More about MQTT & HiveMQ:
www.hivemq.com/blog
@HiveMQ
@dcsquare

75. THANKS
Follow me @goetzchr

76. Credits
All rights for IT Crowd video (YouTube) & photo
belong to Channel4
!
Raspberry Pi by inrepose from Flickr
!
“we are all makers” rights belong to MakerMedia
!
Client/Server Image from University of Regina
!
Other photos are from depositphotos.com