Paper Telecom

A Low-Power CoAP for Contiki
Matthias Kovatsch, Simon Duquennoy, and Adam Dunkels [e-mail] [e-mail] [e-mail]

Monday, 17 Oct 2011

Internet of Things Protocol Stack
Layer
Application Transport Network Adaption MAC Radio Duty Cycling Physical
Matthias Kovatsch – ETH Zürich

Protocol
CoAP / REST Engine (Erbium) UDP IPv6 / RPL 6LoWPAN CSMA / link-layer bursts ContikiMAC IEEE 802.15.4
A Low-Power CoAP for Contiki 2

ContikiMAC

Radio on
D Data frame A ACK frame

Sender

D

D

D

D A

Receiver Channel check

D A

Transmission detected

Matthias Kovatsch – ETH Zürich

A Low-Power CoAP for Contiki

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Link-layer Bursts

Radio on
D Data frame A ACK frame

Sender

D

D

D

D A D A D A D A

Receiver Channel check

D A D A D A D A

Transmission detected

Matthias Kovatsch – ETH Zürich

A Low-Power CoAP for Contiki

4

Constrained Application Protocol (CoAP)
 RESTful Web services for networked embedded devices
 Idealized architectural style of the Web  HTTP for the Internet of Things coap://sky2/ coap://sky1/

coap://sky3/

Matthias Kovatsch – ETH Zürich

A Low-Power CoAP for Contiki

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«Erbium» CoAP for Contiki

 Implements draft-ietf-core-coap-07  Available in the Contiki repository on SourceForge

Matthias Kovatsch – ETH Zürich

A Low-Power CoAP for Contiki

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«Erbium» CoAP
 Reliable UDP transport  Observing resources  Blockwise transfers  Resource discovery  Separate responses

 Blocking client requests
Matthias Kovatsch – ETH Zürich A Low-Power CoAP for Contiki 7

«Erbium» REST Engine
 Resource abstraction

CoRE Link Format title="Hello world"; rt="TemperatureC";

RESOURCE(handle, METHODs, URI-Path, Web Linking info);  Resource handler PERIODIC_RESOURCE(handle, METHODs, URI-Path, info, period);  Additional periodic handler EVENT_RESOURCE(handle, METHODs, URI-Path, info);  Additional event handler Observable

Matthias