MQTT

IoT Internet of Things

- IoT is the inter-networking of physical devices. - Also, call it as "connected devices" and "smart

devices"Areas: - Home automation/Smart home - Industrial automation - Health monitoring devices ..etc

Protocols using in IoT :- MQTT (Message Queue Telemetry Transport)- HTTP (Hypertext Transfer Protocol)- CoAP (Constrained Application Protocol)...etc

MQTT( Message Queuing Telemetry Transport )

- MQTT is a publish/subscribe messaging machine-to-machine (M2M)/"Internet of Things" connectivity protocol

- It was originally developed by IBM and is now an open standard.

- Uses port 1883 and 8883 (over SSL).

MQTT vs HTTP- Lightweight- Uses less battery power- Bandwidth-efficient- Takes 1/2 as much power to keep connection

open- Faster throughput- Less network overhead- Header size is 2 bytes over HTTP has

minimum 26 bytes to 2kb depends on request.

TOPICS:Example 1:Publish: “company/name/vinay”Data/Payload : {“phone”:”1234567890”}

Subscriber: “company/name/vinay”

Example 2:Single level Wildcard: +

Subscriber: “company/+/vinay”

Example 3:Multi level Wildcard: #

Subscriber: “company/#”

Quality Of Service (QoS):

QoS 0: The client/server will deliver the message once, with no confirmation required.

QoS 1: The client/server will deliver the message at least once, confirmation required.

QoS 2: The client/server will deliver the message exactly once, confirmation required.

MQTT Libraries: (Device/ Client)- Paho Mqtt- Mosquitto- MQTT.js ...etc

MQTT Broker Cloud Environment :- IBM Bluemix Watson IoT

- eMQTT (erlang MQTT): Open source

Subscribed topic : iot-2/type/Wi-Fimaster/id/cumu_test_dev1/evt/status/fmt/json

Publish topic : iot-2/type/Wi-Fimaster/id/cumu_test_dev1/cmd/action/fmt/json