Sensor networks are a fundamental building block of Internet of Things (IoT) applications, as they provide the interface to the physical world. In fact, many techniques used for resource-constrained IoT devices originated in the research area of Wireless Sensor Networks (WSNs). This talk will present the transition from research prototypes to standardized Internet protocols, give an overview how sensor networks are connected today (with a practical hands-on), and discuss a few challenges that need to be addressed in the future.

1. Connecting Sensor Networks | 1
Matthias Kovatsch
http://people.inf.ethz.ch/mkovatsc
Matthias Kovatsch
kovatsch@inf.ethz.ch
Virtual IoT Meetup #3
Connecting Sensor Networks
Tuesday, 23 Sep 2014
Virtual IoT Meetup #3
www.meetup.com/Virtual-IoT/

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Matthias Kovatsch
http://people.inf.ethz.ch/mkovatsc
 Agenda
1. Wireless Sensor Networks
2. Introduction to 6LoWPAN
3. IPv6 & 6LoWPAN Setup
 Focus on “Connecting”
 Pointers for Sensor Nodes
4. Outlook
 Questions?
 #virtualiot
 Hangouts Q&A
Connecting Sensor Networks

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http://people.inf.ethz.ch/mkovatsc
Smart Dust in 2000
the advent of Wireless Sensor Networks

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Matthias Kovatsch
http://people.inf.ethz.ch/mkovatsc
e.g., TinyDB
 Focus on resource constraints
 Sink nodes and custom software
Wireless Sensor Networks
Mica2 (AVR)
Tmote Sky / TelosB (MSP430)
BTnode (AVR + Bluetooth)

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Matthias Kovatsch
http://people.inf.ethz.ch/mkovatsc
First Proposals for Low-power IPv4 in 2003
 A. Dunkels. Full TCP/IP for 8-bit Architectures.
In Proceedings MobiSys, San Francisco, CA, USA, 2003
 Z. Shelby, P. Mahonen, J. Riihijarvi, O. Raivio, and P.
Huuskonen. NanoIP: The Zen of Embedded Networking.
In Proceedings ICC, Anchorage, AK, USA, 2003
http://contiki-os.org

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http://people.inf.ethz.ch/mkovatsc
6LoWPAN for Sensor Networks

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Matthias Kovatsch
http://people.inf.ethz.ch/mkovatsc
Low-power IP Stack
Layer Protocol
Application CoAP
Transport UDP
Network IPv6
Adaption 6LoWPAN
MAC CSMA
Radio Duty Cycling IEEE 802.15.4e / ContikiMAC
Physical IEEE 802.15.4

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Matthias Kovatsch
http://people.inf.ethz.ch/mkovatsc
Low-power IP Stack
Layer Protocol
Application CoAP
Transport UDP
Network IPv6 ( + RPL routing protocol )
Adaption 6LoWPAN
MAC CSMA
Radio Duty Cycling IEEE 802.15.4e / ContikiMAC
Physical IEEE 802.15.4

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Matthias Kovatsch
http://people.inf.ethz.ch/mkovatsc
Low-power IP Stack
Layer Protocol
Application CoAP
Transport UDP
Network IPv6
Adaption 6LoWPAN
MAC CSMA
Radio Duty Cycling IEEE 802.15.4e / ContikiMAC
Physical IEEE 802.15.4

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Matthias Kovatsch
http://people.inf.ethz.ch/mkovatsc
Low-power IP Stack
Layer Protocol
Application CoAP
Transport UDP
Network IPv6
Adaption 6LoWPAN
MAC CSMA
Radio Duty Cycling IEEE 802.15.4e / ContikiMAC
Physical IEEE 802.15.4

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Edge Networks
LoWPAN Local
server
Border Router
6LoWPAN adaption
PC
Backbone (LAN)
Internet
Router Server

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http://people.inf.ethz.ch/mkovatsc
Number of fixed bits in prefix
8 bytes prefix 8 bytes interface identifier
IPv6 Addresses
128 bits = 16 bytes
xxxx:xxxx:xxxx:xxxx:yyyy:yyyy:yyyy:yyyy /zz

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Leading zeros can be omitted
Zero blocks can be omitted with “::”
xxxx:xxx: : /zz
IPv6 Addresses
 Localhost
::1/128
 Default route
::/0
 Link-local
FE80::/64
 Multicast
FF00::/8

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Matthias Kovatsch
http://people.inf.ethz.ch/mkovatsc
… prefixes
IPv6 Addressing
LoWPAN
ISP
Router
Border Router
Backbone (LAN)
2001:470:CAFE::/48
2001:470:CAFE:10::/64
2001:470:CAFE::/64
EUI-64 = MAC address
2001:470:CAFE:10: 212:7400:DEAD:BEEF
2001:470:CAFE::1
2001:470:CAFE::10
Mote
Laptop

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 Nice ISP
 Check at
http://www.ipv6forum.com/ipv6_
enabled/isp/approval_list.php
 IPv6 tunnel
 For instance
 Register at
https://tunnelbroker.net/
Your Own IPv6 Prefix

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Your WAN IP
Choose something close

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http://people.inf.ethz.ch/mkovatsc

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Matthias Kovatsch
http://people.inf.ethz.ch/mkovatsc
 Firmware with good IPv6 support
 Pick one that supports your model
 Find lots of support online (flash router, DD-WRT, Tomato, …)
 For instance
 Tomato by Shibby (continuation of TomatoUSB)
http://tomato.groov.pl/
 Good old WRT54GL has not enough flash
for good IPv6 builds
 Model list
http://tomato.groov.pl/?page_id=69
Router

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http://people.inf.ethz.ch/mkovatsc

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 Linksys E900
 Cheap ($ ~30)
 Netgear WRN3500L
 More features ($ ~50)
Router Hardware

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 Perform a hard reset
with the “30/30/30”
 Use the Web interface
to upload new binary
 Search for help
firmware name + router model
Flash Firmware

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Routed /48 (e.g., 2001:470:cafe::)
/48 + ‘1’ (e.g., 2001:470:cafe::1)
Server IPv4 Address
Client IPv6 Address

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ip -6 r add 2001:470:cafe:10::/64 via 2001:470:cafe::10
6LoWPAN prefix Gateway with
border router

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ip6tables -A FORWARD -p udp --dport 5683
–d 2001:470:cafe:10:<mote EUI-64> -j ACCEPT
See ip6tables manual for more options
(e.g., source filtering)

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 Raspberry Pi
 Shortcut: Use a Linux PC (avoids cross-compiling)
 Beagle Bone (Black)
Gateway

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Matthias Kovatsch
http://people.inf.ethz.ch/mkovatsc
 SSH or direct connection
 Add static IPv6 address for routing (see slide 24)
 sudo ip -6 a add 2001:470:cafe::10 dev eth0
 Enable routing in the kernel
 echo "1" > /proc/sys/net/ipv6/conf/all/forwarding
 Install the border router
Gateway Configuration

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Matthias Kovatsch
http://people.inf.ethz.ch/mkovatsc
 Tmote Sky / TelosB
(old, hard to get)
Search “MTM-CM5000-MSP”
 Zolertia Z1
http://zolertia.com/
 OpenMote
(up-to-date, growing support)
http://www.openmote.com/
 Econotag II
http://redwirellc.com/
Border Router Hardware

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Matthias Kovatsch
http://people.inf.ethz.ch/mkovatsc
 Get Contiki
 git clone https://github.com/contiki-os/contiki
 Relevant projects are in contiki/examples/ipv6/
 Seek further help online
 https://github.com/contiki-os/contiki/wiki
 http://www.openmote.com/getting-started-with-contiki-and-openmote/
 Check the 6lbr project by Cetic
 http://cetic.github.io/6lbr/
Contiki OS

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http://people.inf.ethz.ch/mkovatsc
 Old RPL border router
 rpl-border-router running on the mote
 make TARGET=sky border-router.upload
 tunslip6 (in contiki/tools/) running on the gateway
 make tunslip6 (compile on gateway or with cross-compiler)
 New native border router (recommended)
 slip-radio running on the mote
 make TARGET=sky slip-radio.upload
 native-border-router running on the gateway
 make border-router (compile on gateway or with cross-compiler)
Projects in contiki/examples/ipv6/

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sudo ./{tunslip6|border-router.native} 2001:470:cafe:10::1/64
 Opens tun0 interface
 Adds route into 6LoWPAN subnet
Starting the Border Router
$ sudo ./border-router.native 2001:470:cafe:10::1/64
Contiki 3.x started with IPV6, RPL
Rime started with address 1.2.3.4.5.6.7.8
MAC nullmac RDC br-rdc NETWORK sicslowpan
Tentative link-local IPv6 address fe80:0000:0000:0000:0302:0304:0506:0708
RPL-Border router started
********SLIP started on ``/dev/ttyUSB0''
opened tun device ``/dev/tun0''
ifconfig tun0 inet `hostname` up
ifconfig tun0 add 2001:470:cafe:10::1/64
ifconfig tun0
tun0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
inet addr:127.0.1.1 P-t-P:127.0.1.1 Mask:255.255.255.255
inet6 addr: 2001:470:cafe:10::1/64 Scope:Global
[…]
Setting prefix 2001:470:cafe:10::1
created a new RPL dag
Server IPv6 addresses:
0x806a6b8: =>2001:470:cafe:10:212:7400:da0:d748
0x806a6d8: =>fe80::212:7400:da0:d748
Border router address

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http://people.inf.ethz.ch/mkovatsc

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Matthias Kovatsch
http://people.inf.ethz.ch/mkovatsc
 Use Erbium (Er)
CoAP in Contiki
 Examples in contiki/examples/er-rest-example/
 make TARGET=sky er-example-server.upload MOTE=2
Sensor Nodes (“Motes”)
Avoid reprogramming
the border-router/slip-radio

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http://people.inf.ethz.ch/mkovatsc
Mote address

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https://addons.mozilla.org/en-US/firefox/addon/copper-270430/

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Build Applications with CoAP
Web Sensor Nodes
Constrained Application Protocol (CoAP)

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Californium Tutorial: Hands-on with CoAP
http://eclipse.org/californium http://goo.gl/LLQ03w

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Current Efforts

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 Interoperable, scalable security
 Elliptic curve cryptography
 Public key cryptography?
 Crypto hardware acceleration
 DTLS Profiles (DICE)
 Authentication/Authorization in Constrained Environments (ACE)
 Secure multicast?
Next Big Step for Low-power IP

40. Questions?
Matthias Kovatsch https://github.com/mkovatsc/
kovatsch@inf.ethz.ch http://people.inf.ethz.ch/mkovatsc/