Presentation at the Internet of Things Zurich Meetup, Zurich, Switzerland. http://www.meetup.com/IoT-Zurich/events/55029792/

1. CoAP, Copper, and Embedded Web Resources
Matthias Kovatsch
kovatsch@inf.ethz.ch
Tuesday, 03 Apr 2012 Internet of Things Zurich Meetup, Zurich, Switzerland

2. What About Really Cheap Platforms?
Smart
Dust
Matthias Kovatsch – ETH Zürich CoAP, Copper, and Embedded Web Resources 2

3. Outcome
Wireless Sensor Networks
Matthias Kovatsch – ETH Zürich CoAP, Copper, and Embedded Web Resources 3

4. IP Connectivity through 6LoWPAN
IP router
Web server
Matthias Kovatsch – ETH Zürich CoAP, Copper, and Embedded Web Resources 4

5. Constrained Application Protocol (CoAP)
A new Web-like protocol based on REST
GET, PUT, POST, DELETE
URIs
Internet Media Types
Interoperability
Extensible option headers
Common
programming model
Matthias Kovatsch – ETH Zürich CoAP, Copper, and Embedded Web Resources 5

6. The CoAP Universe
 IETF working group «Constrained RESTful Environments»
 RESTful Web services for mote-class devices
 Transparent mapping to HTTP
 Observing Resources publish/subscribe
 Group communication IP multicast
 CoRE Link Format Web linking RFC, discovery
 Caching proxies RESTful caching
 Resource directories sleepy nodes
 Blockwise transfers bulky data
 …
Matthias Kovatsch – ETH Zürich CoAP, Copper, and Embedded Web Resources 6

7. CoAP is Optimized, Binary…
Matthias Kovatsch – ETH Zürich CoAP, Copper, and Embedded Web Resources 7

8. Copper (Cu) CoAP user-agent
Matthias Kovatsch – ETH Zürich CoAP, Copper, and Embedded Web Resources 8

9. Embedded Web Resources
/actuators/leds /config/date /consumption
/debug/channel /config/mode /consumption/consumed
/debug/neighbors /config/time /consumption/generated
/debug/observers /debug/… /debug/…
/debug/routes /sensors/battery /max/power
/sensors/batter /sensors/temp /max/current
y
/sensors/button /sensors/user /max/voltage
/sensors/humidity /set/valve /meter/power
/sensors/light /set/target /meter/current
/sensors/temperature /meter/voltage
/meter/frequency
/meter/phase
/meter/reactive
/reset
/switch
Matthias Kovatsch – ETH Zürich CoAP, Copper, and Embedded Web Resources 9

10. Profiles for Embedded Web Resources
IPSO Profile Smart Energy Profile 2.0
 Pure RESTful design  SOAP-like service design
 Treats CoAP and HTTP equally over REST
 Currently still cryptic identifiers  Currently only defined for
due to size optimizations HTTP, CoAP in the draft
(e.g., /lt for light)
Matthias Kovatsch – ETH Zürich CoAP, Copper, and Embedded Web Resources 10

11. CoAP Open Source Implementations*
Erbium for Contiki Californium in Java Copper for Firefox
 REST Engine  CoAP framework  CoAP user-agent
 For embedded devices  For the back-end  For user interaction
 Enables thin server  Clients, servers,  Integration and testing
architecture and proxies tool
* Available on GitHub:athttps://github.com/mkovatsc Paris, France, Mar 2012: http://www.etsi.org/plugtests/coap/coap.htm
Successfully tested the ETSI IoT CoAP Plugtests,
Matthias Kovatsch – ETH Zürich CoAP, Copper, and Embedded Web Resources 11

12. THANK YOU
Questions?
Matthias Kovatsch – ETH Zürich CoAP, Copper, and Embedded Web Resources 12

13. Protocol Stack
Layer Protocol
Application CoAP
Transport UDP
Network IPv6 / RPL
Adaption 6LoWPAN
MAC CSMA / link-layer bursts
Radio Duty Cycling IEEE 802.15.4e / ContikiMAC
Physical IEEE 802.15.4
Matthias Kovatsch – ETH Zürich CoAP, Copper, and Embedded Web Resources 13

14. CoAP Message Format
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Ver| T | OC | Code | Message ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Options (if any) ... | (Terminator) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Payload (if any) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Matthias Kovatsch – ETH Zürich CoAP, Copper, and Embedded Web Resources 14

15. CoAP Option Encoding
0 1 2 3 4 5 6 7
+---+---+---+---+---+---+---+---+
| Option Delta | Length | for 0..14
+---+---+---+---+---+---+---+---+
| Option Value ...
+---+---+---+---+---+---+---+---+
for 15..270
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| Option Delta | 1 1 1 1 | Length - 15 |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
| Option Value ...
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
Matthias Kovatsch – ETH Zürich CoAP, Copper, and Embedded Web Resources 15