Border Router with Raspberry Pi for LLN with TelosBs

This tutorial aims to create a IPv6 Low-power and Lossy Network (LLN) of TelosB motes with a Rapsberry Pi (RPi) as a border router (LBR) to connect to other IPv6 networks. RPi is configured for routing traffic from the LLN to other IPv6 networks by creating a TUN network interface. An alternative to setup a LLN is to configure a bridge (TAP) as in Cetic-6LBR (https://github.com/cetic/6lbr/)

We are going to have two IPv6 networks associated to two network interfaces of the LBR RPi as shown in Fig.1.

Fig.1: Deployment

LBR
- eth0: bbbb::1/64 (Physical Ethernet interface to normal IPv6 network)
- tun0: aaaa::1/64 (TUN interface to LLN)

IPv6 Network:
- bbbb::2

LLN:
- aaaa::212:7400:13cb:44 (slip-radio)
- aaaa::212:7400:13cb:101a
- aaaa::212:7400:13ca:f3ac

1. LLN Network (see here)

- Flash radio-slip mote (contiki-2.7/examples/ipv6/slip-radio) to use as an IEEE 802.15.4 interface
- Flash other TelosB for LLN nodes (e.g., contiki-2.7/examples/ipv6/udp-server)

2. IPv6 Network
- Configure a machine with bbbb::/64 address (example with a Linux)
# sudo vi /etc/network/interfaces
auto eth0
iface eth0 inet6 static
address bbbb::2
netmask 64
gateway bbbb::100 (border router address)

(you may need to deactivate other network interfaces to check if it works properly)

3. RPi Border Router
Prepare RPi OS
- Download Raspbian

- Create a boot disk using SD card (>4G) using Win32 DiskImager
(Check here for Raspbian essentials)

- Plug radio-slip mote to RPi, recognized as /dev/ttyUSB0

- Enable IPv6 module?

# sudo modprobe ipv6
or to automatically enable it at boot, add ipv6 on a line at the end of /etc/modules.

- Enable IPv6 forwarding
# sudo sysctl -w net.ipv6.conf.all.forwarding=1

or edit /etc/sysctl.conf uncomment the line: net.ipv6.conf.all.forwarding=1

- Configure IPv6 address for eth0
# sudo vi /etc/network/interfaces
auto eth0
iface eth0 inet6 static
address bbbb::1
netmask 64

- Download contiki-2.7 source
- Go to examples/ipv6/native-border-router
- Fix source and build 
# vi border-router.c, line 161: remove ; (contiki 2.7 bug)
# vi slip-config.c, line 76: change -1 to 255 (RPi kernel??)
# make

- Run border router
# sudo modprobe ipv6 (optional)
# sudo sysctl -w net.ipv6.conf.all.forwarding=1 (optional)
# sudo ./border-router.native -L -v6 aaaa::1/64 (debug, ttyUSB0, 115200)

Autostart the border-router.native by adding it to /etc/rc.local (optional)
path_to_border-router.native aaaa::1/64

ex: /home/pi/contiki-2.7/examples/ipv6/native-border-router/border-router.native aaaa::1/64 &

4. Test

From IPv6 network computer ping to LLN
Ping: ping6 aaaa::212:7400:13cb:101a
Web browser: aaaa::212:7400:13cb:44