MQTT is an alternative lightweight and highly reliable protocol compared to the HTTP. In these series of slides I reiterate the strengths of the MQTT protocol. Stephen Nicolas shares pretty exciting data on MQTT-HTTP comparison http://stephendnicholas.com/archives/1217

1. MQTT
Boadu A. Charles Jnr

2. IoT Ecosystem
TinkerKit Relay
Module
ESP8266
Air Conditioner
Internet
ThingSpeak
Phone
Twitter
#thinkspeak #chill
3.3V
240V
2016-01-20 01:23:24 UTC,31,1

3. IoT Ecosystem
ESP8266
Internet
HTTP

4. MQTT (Message Queue Telemetry
Transport) is a publish-subscribe
messaging protocol designed for
lightweight M2M communications.
MQTT

5. Communication Model
Has client-server model.
Communicates over TCP.
Server accepts requests.
Has client-server model.
Communicates over TCP.
Broker accepts messages.
HTTP MQTT

6. Verbs
GET
POST
PUT
PATCH
DELETE
Connect
Subscribe
UnSubscribe
Publish
Disconnect
HTTP MQTT

7. Implementation
https://eclipse.org/community/eclipse_newsletter/2014/february/article2.php
Client A
Client C Client B
Broker
subscribe “human-presence”
subscribe “human-presence”

8. Implementation
https://eclipse.org/community/eclipse_newsletter/2014/february/article2.php
Client A
Client C Client B
Broker
“human-presence” = “motion detected”
“human-presence” = “motion detected”publish “human-presence” “motion detected”

9. Quality of Service
Makes communication in
unreliable networks a lot easier
because it handles retransmission
and guarantees the delivery of the
message.

10. Quality of Service
• Fire and forget (0).
Client sends message to broker. Doesn’t care
what happens to it.
• Deliver at least once (1).
Client only destroys copy of message when
acknowledgement is received from broker.
• Deliver exactly once (2).
Multiple levels of checks and balances until it is
established that message has been sent exactly
once.

11. Last Will Testament
Configure a connection to send
message to a specified client in
case the connecting client’s
connection closes in an ungraceful
manner.

12. Persistent Sessions
In the event that the client goes
offline, the broker stores all
messages that the client has
subscribed to and notifies the
client of all such messages once it
comes back online.

13. Security
MQTT brokers may require
username and password
authentication from clients to
connect. To ensure privacy, the
TCP connection may be encrypted
with SSL/TLS.

14. IoT Communication Metrics

15. • Response times.
• Throughput.
• Lower battery use.
• Lower bandwidth.
Communication Metrics

16. Response Times
https://en.wikipedia.org/wiki/HTTP_persistent_connection#/media/File:HTTP_persistent_connection.svg
HTTP MQTT

17. Response Times
Credit: Stephen Nicolas
http://stephendnicholas.com/archives/1217

18. Low Battery Use
Initial connection to server
Credit: Stephen Nicolas
http://stephendnicholas.com/archives/1217

19. Low Battery Use
Subsequent connections to server
Credit: Stephen Nicolas
http://stephendnicholas.com/archives/1217

20. GET
/channels/78955/fields/1/last.csv?results=1
HTTP/
1.1
Host:
api.thingspeak.com
User-­‐Agent:
curl/7.43.0
Accept:
*/*
Lower Bandwidth- HTTP Request

21. HTTP/1.1
200
OK
Content-­‐Type:
text/csv;
charset=utf-­‐8
Transfer-­‐Encoding:
chunked
X-­‐Cnection:
close
Status:
200
OK
X-­‐Frame-­‐Options:
ALLOWALL
Access-­‐Control-­‐Allow-­‐Origin:
*
Access-­‐Control-­‐Allow-­‐Methods:
GET,
POST,
PUT,
OPTIONS,
DELETE,
PATCH
Access-­‐Control-­‐Allow-­‐Headers:
origin,
content-­‐type,
X-­‐
Requested-­‐With
Access-­‐Control-­‐Max-­‐Age:
1800
Lower Bandwidth - HTTP Response

22. ETag:
"7fc3e3807361a7e2b8f3cb302e4a3bab"
Cache-­‐Control:
max-­‐age=0,
private,
must-­‐revalidate
X-­‐Request-­‐Id:
81b2114a-­‐32a3-­‐4bfa-­‐8106-­‐26c75a350760
X-­‐Runtime:
0.011029
X-­‐Powered-­‐By:
Phusion
Passenger
4.0.57
Date:
Wed,
20
Jan
2016
22:22:30
GMT
Server:
nginx/1.9.3
+
Phusion
Passenger
4.0.57
Vary:
Accept-­‐Encoding,
User-­‐Agent
created_at,entry_id,field1
2016-­‐01-­‐20
14:59:45
UTC,32,1
Lower Bandwidth - HTTP Response Contd.
HTTP is simply Verbose. MQTT has a fixed 1 byte header
and an optional 2 byte identifier header.

23. MQTT Implementation

24. Server Implementation
Like ThingSpeak, with CloudMQTT you can create and
manage device states online but this time using the MQTT
protocol.

25. Client Implementation
Eclipse Paho provides open-source client implementations
of MQTT.
Supported Platforms
• C client for Windows/Unix/Mac
• Java client and utilities
• Android service
• Python client
• JavaScript client
• C/C++ MQTT Embedded clients
• .Net and WinRT client (M2Mqtt)
http://www.hivemq.com/blog/mqtt-security-fundamentals-wrap-up

26. Client Implementation for ESP8266
https://github.com/adafruit/Adafruit_MQTT_Library
https://learn.adafruit.com/adafruit-io-basics-digital-
output/esp8266
https://github.com/adafruit/Adafruit_MQTT_Library/
blob/master/examples/mqtt_esp8266/
mqtt_esp8266.ino
Adafruit Huzzah

27. Notable Platforms That Use
MQTT

28. Popular Users

29. Thank You

30. http://www.hivemq.com
http://www.hivemq.com/blog/how-to-get-started-with-mqtt
Further Reading