OpenThread released by Google is an open-source implementation of the Thread networking protocol. Google Nest has released OpenThread to make the technology used in Nest products broadly available to developers to accelerate the development of products for the connected home.

The Thread specification defines an IPv6-based reliable, secure and low-power wireless device-to-device communication protocol for home applications. OpenThread implements all Thread networking layers including IPv6, 6LoWPAN, IEEE 802.15.4 with MAC security, Mesh Link Establishment, and Mesh Routing.

This Codelab will walk you through simulating a Thread network on emulated devices using Docker.

What you'll learn

What you'll need

This Codelab is designed to use Docker on a Linux, Mac OS X, or Windows machine. Linux is the recommended environment.

Install Docker

Install Docker on the OS of your choice.

Download Docker

Pull the Docker image

Once Docker is installed, open a terminal window and pull the openthread/codelab_otsim Docker image. This image features OpenThread and wpantund pre-built and ready to use for this Codelab.

$ docker pull openthread/codelab_otsim:latest

Note that it may take a few minutes to completely download.

In a terminal window, start a Docker container from the image and connect to its bash shell:

$ docker run --name codelab_otsim_ctnr -it --rm \
   --sysctl net.ipv6.conf.all.disable_ipv6=0 \
   --cap-add=net_admin openthread/codelab_otsim bash

Note the flags, which are required for this Codelab:

Once in the container, you should have a prompt similar to this:

root@c0f3912a74ff:/#

In the above example, the c0f3912a74ff is the Container ID. The Container ID for your instance of the Docker container will differ from the one shown in the prompts for this Codelab.

Using Docker

This Codelab assumes you know the basics of using Docker. You should remain in the Docker container for the entirety of the Codelab.

The example application you'll use for this Codelab demonstrates a minimal OpenThread application that exposes the OpenThread configuration and management interfaces via a basic command-line interface (CLI).

This exercise takes you through the minimal steps required to ping one emulated Thread device from another emulated Thread device.

The figure below describes a basic Thread network topology. For this exercise, we'll emulate the two nodes within the green circle: a Thread Leader and Thread Router with a single connection between them.

Create the network

1. Start Node 1

If you haven't done so already, in a terminal window, start the Docker container and connect to its bash shell:

$ docker run --name codelab_otsim_ctnr -it --rm \
   --sysctl net.ipv6.conf.all.disable_ipv6=0 \
   --cap-add=net_admin openthread/codelab_otsim bash

In the Docker container, navigate to the openthread directory and spawn the CLI process for an emulated Thread device using the ot-cli-ftd binary.

root@c0f3912a74ff:/# cd ~/src/openthread
root@c0f3912a74ff:/# ./output/x86_64-unknown-linux-gnu/bin/ot-cli-ftd 1

This binary implements an OpenThread device emulated on top of POSIX. The IEEE 802.15.4 radio driver is implemented on top of UDP (IEEE 802.15.4 frames are passed within UDP payloads).

The argument of 1 is a file descriptor that represents the least-significant bits of the "factory-assigned" IEEE EUI-64 for the emulated device. This value is also used when binding to a UDP port for IEEE 802.15.4 radio emulation (port = 9000 + file descriptor). Each instance of an emulated Thread device in this Codelab will use a different file descriptor.

Note: Only use file descriptors of 1 or greater as noted in this Codelab when spawning the process for an emulated device. A file descriptor of 0 is reserved for other use.

If you don't see the > prompt after running this command, press enter.

Create a new Operational Dataset and commit it as the active one. The Operational Dataset is the configuration for the Thread network you are creating.

> dataset init new
Done
> dataset
Active Timestamp: 1
Channel: 20
Channel Mask: 07fff800
Ext PAN ID: d6263b6d857647da
Mesh Local Prefix: fd61:2344:9a52:ede0/64
Master Key: e4344ca17d1dca2a33f064992f31f786
Network Name: OpenThread-c169
PAN ID: 0xc169
PSKc: ebb4f2f8a68026fc55bcf3d7be3e6fe4
Security Policy: 0, onrcb
Done
> dataset commit active
Done

Bring up the IPv6 interface:

> ifconfig up
Done

Start Thread protocol operation:

> thread start
Done

Wait a few seconds and verify that the device has become the Thread Leader. The Leader is the device responsible for managing router ID assignment.

> state
leader
Done

View the IPv6 addresses assigned to Node 1's Thread interface (your output will be different):

> ipaddr
fd61:2344:9a52:ede0:0:ff:fe00:fc00
fd61:2344:9a52:ede0:0:ff:fe00:5000
fd61:2344:9a52:ede0:d041:c5ba:a7bc:5ce6
fe80:0:0:0:94da:92ea:1353:4f3b
Done

Note the specific IPv6 address types:

Mesh-local address types are classified further:

Identify the EID in your console output make a note of it for later use. In the sample output above, the EID is:

fd61:2344:9a52:ede0:d041:c5ba:a7bc:5ce6

2. Start Node 2

Open a new terminal and execute a bash shell in the currently running Docker container to use for Node 2.

$ docker exec -it codelab_otsim_ctnr bash

At this new bash prompt, navigate to the openthread directory and spawn the CLI process. This is your second emulated Thread device:

root@c0f3912a74ff:/# cd ~/src/openthread
root@c0f3912a74ff:/# ./output/x86_64-unknown-linux-gnu/bin/ot-cli-ftd 2

If you don't see the > prompt after running this command, press enter.

Configure the Thread Master Key and PAN ID, using the same values as Node 1's Operational Dataset:

> dataset masterkey e4344ca17d1dca2a33f064992f31f786
Done
> dataset panid 0xc169
Done
> dataset commit active
Done

Bring up the IPv6 interface:

> ifconfig up
Done

Start Thread protocol operation:

> thread start
Done

The device will initialize itself as a Child. A Thread Child is equivalent to an End Device, which is a Thread device that transmits and receives unicast traffic only with a Parent device.

> state
child
Done

Within 2 minutes you should see the state switch from child to router. A Thread Router is capable of routing traffic between Thread devices. It is also referred to as a Parent.

> state
router
Done

Verify the network

An easy way to verify the mesh network is to look at the router table.

1. Check connectivity

On Node 2, get the RLOC16. The RLOC16 is the last 16 bits of the device's RLOC IPv6 address.

> rloc16
5800
Done

On Node 1, check the router table for Node 2's RLOC16. Make sure Node 2 has switched to the router state first.

> router table
| ID | RLOC16 | Next Hop | Path Cost | LQ In  | LQ Out  | Age | Extended MAC     |
+----+--------+----------+-----------+--------+---------+-----+------------------+
| 20 | 0x5000 |       63 |         0 |      0 |       0 |   0 | 96da92ea13534f3b |
| 22 | 0x5800 |       63 |         0 |      3 |       3 |  23 | 5a4eb647eb6bc66c |

Node 1's RLOC of 0x5800 is found in the table, confirming that it is connected to the mesh.

2. Ping Node 1 from Node 2

Verify connectivity between the two emulated Thread devices. In Node 2, ping the EID assigned to Node 1:

> ping fd61:2344:9a52:ede0:d041:c5ba:a7bc:5ce6
> 16 bytes from fd61:2344:9a52:ede0:d041:c5ba:a7bc:5ce6: icmp_seq=1 hlim=64 time=12ms

Press enter to return to the > CLI prompt.

Test the network

Now that you can successfully ping between two emulated Thread devices, test the mesh network by taking one node offline.

Return to Node 1 and stop Thread:

> thread stop
Done

Switch to Node 2 and check the state. Within two minutes, Node 2 detects that the leader (Node 1) is offline, and you should see Node 2 transition to be the leader of the network:

> state
router
Done
...
> state
leader
Done

Once confirmed, stop Thread and factory reset Node 2 before exiting back to the Docker bash prompt. A factory reset is done to ensure that the Thread network credentials we used in this exercise are not carried over to the next exercise.

> thread stop
Done
> factoryreset
>
> exit
root@c0f3912a74ff:/#

You may have to press enter a few times to bring the > prompt back after a factoryreset command. Do not exit the Docker container.

Also factory reset and exit Node 1:

> factoryreset
>
> exit
root@c0f3912a74ff:/#

See the OpenThread CLI Reference to explore all available CLI commands.

In the previous exercise, you set up a Thread network with two simulated devices and verified connectivity. However, this only allows unauthenticated IPv6 link-local traffic to pass between devices. To route global IPv6 traffic between them (and the Internet via a Thread border router), nodes must be authenticated.

In order to authenticate, one device must act as a Commissioner. The Commissioner is the currently elected authentication server for new Thread devices, and the authorizer for providing the network credentials required for the devices to join the network.

In this exercise, we will use the same two-node topology as before. For authentication, the Thread Leader will act as the Commissioner, the Thread Router as a Joiner.

Docker

For each Node (terminal window) in the remaining exercises, make sure you are running the Docker container with the OpenThread build. If continuing from the previous exercise, you should still have two bash prompts within the same Docker container already open. If not, see the Docker Troubleshooting step, or simply redo the Simulate a Thread network exercise.

1. Create a network

In Node 1, spawn the CLI process:

root@c0f3912a74ff:/# cd ~/src/openthread
root@c0f3912a74ff:/# ./output/x86_64-unknown-linux-gnu/bin/ot-cli-ftd 1

If you don't see the > prompt after running this command, hit enter.

Create a new Operational Dataset, commit it as the active one, and start Thread:

> dataset init new
Done
> dataset
Active Timestamp: 1
Channel: 12
Channel Mask: 07fff800
Ext PAN ID: e68d05794bf13052
Mesh Local Prefix: fd7d:ddf7:877b:8756/64
Master Key: a77fe1d03b0e8028a4e13213de38080e
Network Name: OpenThread-8f37
PAN ID: 0x8f37
PSKc: f9debbc1532487984b17f92cd55b21fc
Security Policy: 0, onrcb
Done
> dataset commit active
Done
> ifconfig up
Done
> thread start
Done

Wait a few seconds and verify that the device has become a Thread Leader:

> state
leader
Done

2. Start the Commissioner role

While still on Node 1, start the Commissioner role:

> commissioner start
Done

Allow any Joiner (by using the * wildcard) with the J01NME Joiner Credential to commission onto the network. A Joiner is a device that is added by a human administrator to a commissioned Thread Network.

> commissioner joiner add * J01NME
Done

3. Start the Joiner role

In a second terminal window, in the Docker container, spawn a new CLI process. This is Node 2.

root@c0f3912a74ff:/# cd ~/src/openthread
root@c0f3912a74ff:/# ./output/x86_64-unknown-linux-gnu/bin/ot-cli-ftd 2

On Node 2, enable the Joiner role using the J01NME Joiner Credential.

> ifconfig up
Done
> joiner start J01NME
Done

... wait a few seconds for confirmation ...

Join success

As a Joiner, the device (Node 2) has successfully authenticated itself with the Commissioner (Node 1) and received the Thread Network credentials.

Now that Node 2 is authenticated, start Thread:

> thread start
Done

4. Validate network authentication

Check the state on Node 2, to validate that it has now joined the network. Within two minutes, Node 2 transitions from child to router:

> state
child
Done
...
> state
router
Done

5. Reset configuration

To prepare for the next exercise, reset the configuration. On each Node, stop Thread, do a factory reset, and exit the emulated Thread device:

> thread stop
Done
> factoryreset
>
> exit
root@c0f3912a74ff:/#

You may have to press enter a few times to bring the > prompt back after a factoryreset command.

For this exercise, we are going to simulate one CLI instance (a single embedded SoC Thread device) and one Network Co-Processor (NCP) instance.

wpantund is a user-space network interface driver/daemon that provides a native IPv6 network interface to a low-power wireless NCP. It can be used to simplify supporting Thread connectivity on Unix-like operating systems, and is designed to marshall all access to the NCP, ensuring that it always remains in a consistent and well-defined state.

wpanctl is a CLI provided by wpantund to manage and configure the NCP. Using this, we'll connect the NCP to the network created by the Thread device.

Docker

For each Node (terminal window) in this exercise, make sure you are running the Docker container with the OpenThread build. If continuing from the previous exercise, you should have two bash prompts within the same Docker container already open. If not, see the Docker Troubleshooting step.

Use wpantund

This exercise will use three terminal windows, each connected to a bash prompt in our Docker container. The three windows correspond to the following:

  1. CLI instance of an emulated Thread device (Node 1)
  2. wpantund process
  3. wpanctl CLI instance

1. Start Node 1

In the first terminal window, spawn the CLI process for your emulated Thread device:

root@c0f3912a74ff:/# cd ~/src/openthread
root@c0f3912a74ff:/# ./output/x86_64-unknown-linux-gnu/bin/ot-cli-ftd 1

If you don't see the > prompt after running this command, hit enter.

Create a new Operational Dataset, commit it as the active one, and start Thread:

> dataset init new
Done
> dataset
Active Timestamp: 1
Channel: 13
Channel Mask: 07fff800
Ext PAN ID: 97d584bcd493b824
Mesh Local Prefix: fd55:cf34:dea5:7994/64
Master Key: ba6e886c7af50598df1115fa07658a83
Network Name: OpenThread-34e4
PAN ID: 0x34e4
PSKc: 38d6fd32c866927a4dfcc06d79ae1192
Security Policy: 0, onrcb
Done
> dataset commit active
Done
> ifconfig up
Done
> thread start
Done

View the IPv6 addresses assigned to Node 1's Thread interface:

> ipaddr
fd55:cf34:dea5:7994:0:ff:fe00:fc00
fd55:cf34:dea5:7994:0:ff:fe00:d000
fd55:cf34:dea5:7994:460:872c:e807:c4ab
fe80:0:0:0:9cd8:aab6:482f:4cdc
Done
>

As explained in the Simulate a Thread network step, one address is link-local (fe80) and three are mesh-local (fd). The EID is the mesh-local address that does not contain ff:fe00 in the address. In this sample output, the EID is fd55:cf34:dea5:7994:460:872c:e807:c4ab.

Identify the specific EID from your ipaddr output, which will be used to communicate with the node.

2. Start wpantund

In the second terminal window, create a tun device node and set read/write permissions:

root@c0f3912a74ff:/# mkdir -p /dev/net && mknod /dev/net/tun c 10 200
root@c0f3912a74ff:/# chmod 600 /dev/net/tun

This device is used for packet transmission and receipt in virtual devices. You may get an error if the device has already been created—this is normal and can be ignored.

Restart the D-Bus daemon in your container:

root@c0f3912a74ff:/# service dbus restart

Navigate to the openthread directory, and start wpantund with an interface of utun6:

root@c0f3912a74ff:/# cd ~/src/openthread
root@c0f3912a74ff:/# wpantund -o Config:NCP:SocketPath \
    "system:output/x86_64-unknown-linux-gnu/bin/ot-ncp-ftd 2" \
    -o Daemon:SyslogMask " -info" \
    -o Config:TUN:InterfaceName utun6

When successful, wpantund generates output similar to the following:

wpantund[66]: Starting wpantund 0.08.00d (May 24 2019 23:14:00) . . .
wpantund[66]:         SOURCE_VERSION = 0.07.01-124-g038e8b0
wpantund[66]:         BUILD_VERSION = 0.07.01-153-g6752c40
wpantund[66]: Configuration file "/etc/wpantund.conf" read.
wpantund[66]: Ready. Using DBUS bus ":1.0"
wpantund[66]: Running as root without dropping privileges!
wpantund[67]: About to exec "output/x86_64-unknown-linux-gnu/bin/ot-ncp-ftd 2"
wpantund[66]: [-NCP-]: NCP was reset (STATUS_RESET_POWER_ON, 112)
wpantund[66]: State change: "uninitialized" -> "offline"
wpantund[66]: NCP is running "OPENTHREAD/20180926-00638-g4aca0256; POSIX; May 24 2019 23:17:23"
wpantund[66]: Driver is running "0.08.00d (0.07.01-124-g038e8b0/0.07.01-153-g6752c40; May 24 2019 23:14:00)"
wpantund[66]: Network is not joinable
wpantund[66]: Resetting interface(s). . .
wpantund[66]: Finished initializing NCP

3. Use wpanctl to join the network

The network interface is currently down because we haven't told wpantund to connect to anything yet. This is where wpanctl comes in.

Open a third terminal window and execute the existing container:

$ docker exec -it codelab_otsim_ctnr bash

Once in the container, start wpanctl for the interface utun6:

root@c0f3912a74ff:/# wpanctl -I utun6
wpanctl:utun6>

Check the status of the interface you just created:

wpanctl:utun6> status
utun6 => [
        "NCP:State" => "offline"
        "Daemon:Enabled" => true
        "NCP:Version" => "OPENTHREAD/20180926-00638-g4aca0256; POSIX; May 24 2019 23:17:23"
        "Daemon:Version" => "0.08.00d (0.07.01-124-g038e8b0/0.07.01-153-g6752c40; May 24 2019 23:14:00)"
        "Config:NCP:DriverName" => "spinel"
        "NCP:HardwareAddress" => [18B4300000000002]
]

Use the scan command to see the network you created earlier on Node 1:

wpanctl:utun6> scan
   | Joinable | NetworkName        | PAN ID | Ch | XPanID           | HWAddr           | RSSI
---+----------+--------------------+--------+----+------------------+------------------+------
 1 |       NO | "OpenThread-34e4"  | 0x34E4 | 13 | 97D584BCD493B824 | 9ED8AAB6482F4CDC |  -20

Note the row index of 1 (the first column in the table). You'll need this to join the network.

Add the network key from Node 1's Operational Dataset to the interface:

wpanctl:utun6> set Network:Key --data ba6e886c7af50598df1115fa07658a83

Join the network using the join command and the row index from the earlier scan:

wpanctl:utun6> join 1
Joining "OpenThread-34e4" 97D584BCD493B824 as node type "end-device"
Successfully Joined!

A quick status check now yields more information:

wpanctl:utun6> status
utun6 => [
        "NCP:State" => "associated"
        "Daemon:Enabled" => true
        "NCP:Version" => "OPENTHREAD/20180926-00638-g4aca0256; POSIX; May 24 2019 23:17:23"
        "Daemon:Version" => "0.08.00d (0.07.01-124-g038e8b0/0.07.01-153-g6752c40; May 24 2019 23:14:00)"
        "Config:NCP:DriverName" => "spinel"
        "NCP:HardwareAddress" => [18B4300000000002]
        "NCP:Channel" => 13
        "Network:NodeType" => "end-device"
        "Network:Name" => "OpenThread-34e4"
        "Network:XPANID" => 0x97D584BCD493B824
        "Network:PANID" => 0x34E4
        "IPv6:LinkLocalAddress" => "fe80::544f:440:b6e:9339"
        "IPv6:MeshLocalAddress" => "fd55:cf34:dea5:7994:8bd3:3d1d:da77:abe3"
        "IPv6:MeshLocalPrefix" => "fd55:cf34:dea5:7994::/64"
        "com.nestlabs.internal:Network:AllowingJoin" => false
]

Quit wpanctl and ping Node 1, using its EID with the ping6 command. If the wpantund interface is successfully joined to and communicating with the Thread network, the ping succeeds.

wpanctl:utun6> quit

root@c0f3912a74ff:/# ping6 fd55:cf34:dea5:7994:460:872c:e807:c4ab
PING fd55:cf34:dea5:7994:460:872c:e807:c4ab (fd55:cf34:dea5:7994:460:872c:e807:c4ab): 56 data bytes
64 bytes from fd55:cf34:dea5:7994:460:872c:e807:c4ab: icmp_seq=0 ttl=64 time=4.568 ms
64 bytes from fd55:cf34:dea5:7994:460:872c:e807:c4ab: icmp_seq=1 ttl=64 time=6.396 ms
64 bytes from fd55:cf34:dea5:7994:460:872c:e807:c4ab: icmp_seq=2 ttl=64 time=7.594 ms
64 bytes from fd55:cf34:dea5:7994:460:872c:e807:c4ab: icmp_seq=3 ttl=64 time=5.461 ms
--- fd55:cf34:dea5:7994:460:872c:e807:c4ab ping statistics ---
4 packets transmitted, 4 packets received, 0% packet loss
round-trip min/avg/max/stddev = 4.568/6.005/7.594/1.122 ms

You can also check the wpantund log in the second terminal window to confirm the scan by wpanctl, as well as the successful join:

wpantund[66]: Scan -> Name:OpenThread-34e4  , PanId:0x34E4, Ch:13, Joinable:NO , XPanId:0x97D584BCD493B824, HwAddr:0x9ED8AAB6482F4C24, RSSI:-20 , LQI:0  , ProtoId:3  , Version: 0, ShortAddr:0xFFFF
wpantund[66]: State change: "offline" -> "associating"
wpantund[66]: State change: "associating" -> "associated"
wpantund[66]: Node type change: "unknown" -> "end-device"
wpantund[66]: Adding address "fe80::4a52:6216:6eb7:98fc/64" to NCP

If you have exited the Docker container bash prompts, you may need to check if it's running and restart / reenter as needed.

To show which Docker containers are running:

$ docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
505fc57ffc72        codelab_otsim       "bash"              10 minutes ago      Up 10 minutes                           codelab_otsim_ctnr

To show all Docker containers (both running and stopped):

$ docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
505fc57ffc72        codelab_otsim       "bash"              10 minutes ago      Up 10 minutes                           codelab_otsim_ctnr

If you don't see container codelab_otsim_ctnr in the output of either docker ps command, run it again:

$ docker run --name codelab_otsim_ctnr -it --rm \
   --sysctl net.ipv6.conf.all.disable_ipv6=0 \
   --cap-add=net_admin openthread/codelab_otsim bash

If the container is stopped (listed in docker ps -a but not docker ps), restart it:

$ docker start -i codelab_otsim_ctnr

If the Docker container is already running (listed in docker ps), reconnect to the container in each terminal:

$ docker exec -it codelab_otsim_ctnr bash

You've successfully simulated your first Thread network using OpenThread. Awesome!

In this Codelab you learned how to:

To learn more about Thread and OpenThread, explore these references:

Or, try using OpenThread Border Router in a Docker container!