Internet of Internet of Things

Vassil Kalkov

github : kalkov

twitter : @versicolor

10.01.2015

14,500,000,000 devices

122 new devices every second

2020

50,000,000,000 devices

255 new devices every second

source

Transport

Challenges

• Realtime
• Publishing one to many
• Listening for events as they happen
• Small packets of data from small devices
• Unreliable networks

Application Layers

• HTTP
• CoAP
• MQTT

HTTP

TCP Request/Response

Pros

• Well Known

Cons

• Polling
• One Way
• One to one
• Big Header
• More bytes
• no QoS

CoAP

Constrained Application Protocol

Binary HTTP like on UDP

• Request/Response (HTTP verbs, HTTP like status codes)
• Options (HTTP headers like, but binary)
• DTLS for Security

CoAP messages

• Non Confirmable
• Confirmable
• Observe
• Resource discovery "/.well-known/core"

MQTT

Message Queue Telemetry Transport

TCP

• Publish/Subscribe
• Topics
• Asynchronous
• Lightweight
• Payload agnostic
• QoS (Quality of Service)
• MQTT over Websockets
• Bridging
• SSL

MQTT Topics

Topics

• "/olimex/A10/temp"
• "/olimex/A20/temp"

Subscribe

• "/olimex/A10/temp"
• "/olimex/+/temp"
• "/olimex/#"
• "#"

MQTT QoS

• QoS 0 : At most one (fire and forget)
• QoS 1 : At least one
• Qos 2 : Exactly one

MQTT Brokers

• Mosquitto
• HiveMQ
• Apache ActiveMQ
• others

MQTT-SN

MQTT for Sensor Networks

UDP

Not included

• XMPP
• AMQP

Which one?

• Devices : How much are they constrained?
• Network : How reliable is it?
• Message rate : How many messages? QoS?

Conclusion

Protocol choice depends on scenario. Complex systems can use many protocols.

THE END