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Silk is a fully automated test platform for validating OpenThread function, feature and system performance with real devices. This codebase is Python 3 compatible. The initial supported device is Nordic nRF52840 Development board.

Silk runs on a Raspberry Pi or an ubuntu Linux PC.


Install libraries and dependencies:

cd silk

Install and Build:

sudo make install-cluster


The project can create a Python virtualenv under env directory, which avoids collisions with system managed packages. Some of the packages used by this project tend to collide with apt managed packages (python3-urllib3 and python3-psutil, for example), and will cause some system tools to fail. This option properly sets up a Python venv that doesn't install to system Python dist-packages path.

This option is by default not applied, since most of the testbeds don't have this problem, because they might not have tools that depend on those libraries; but for development environments that do, it can be activated with:

cd silk
./ -v

Install and Build:

sudo make install-cluster-venv

To run any test script using venv, use full path of Python in venv, i.e. sudo ./env/bin/python3 silk/unit_tests/



Silk relies on configuration files to determine what devices that are connected to your computer are eligible to be used in tests.

An example of hwconfig.ini is in silk/tests folder.

The hardware model should be defined as 'Nrf52840' or 'NordicSniffer' in hwconfig.ini file. A cluster ID should be assigned to the config file as well, providing an offset for node IDs for visualizing multiple clusters by the same OTNS service. Attaching clusters with the same ID to the OTNS service could result in conflicts.

ClusterID: 0
LayoutCenter: 300, 300
LayoutRadius: 100

HwModel: Nrf52840
HwRev: 1.0
InterfaceSerialNumber: E1A5012E8A7D
USBInterfaceNumber: 1
DutSerial: 683536778
OTNSVisPosition: 200, 200

HwModel: NordicSniffer
HwRev: 1.0
InterfaceSerialNumber: E992D833CBAF
USBInterfaceNumber: 1
DutSerial: 683906489

A tool called usbinfo is installed as part of Silk which can be used to find out the Interface Serial Number and Usb Interface Number. DutSerial is the SN number printed on the chip or displayed by usbinfo for J-Link product.


Silk reads thread mode (NCP or RCP mode) from clusters.conf which should be added to /opt/openthread_test folder.

An example of clusters.conf is in silk/config folder.

Run test

usage: [-h] [-d ResPath] [-c ConfFile] [-v X] [-s OtnsServer] P [P ...]

Run a suite of Silk Tests
positional arguments:
  P                     test file search pattern
optional arguments:
  -h, --help            show this help message and exit
  -d ResPath, --results_dir ResPath
                        Set the directory path for test results
  -c ConfFile, --hwconfig ConfFile
                        Name the hardware config file
  -v X, --verbose X, --verbosity X
                        Set the verbosity level of the console (0=quiet,
                        1=default, 2=verbose)
  -s OtnsServer, --otns OtnsServer,
                        Set the OTNS server address to send OTNS messages to

There is an example of test run script under unit_tests folder.

Using OTNS

OpenThread Network Simulator is a Thread network visualization and management tool. Using this tool the topology and messages of a network in Silk's control could be visualized. Run the following to install OTNS. Note that it requires Go which can be installed from, after which $(go env GOPATH)/bin should be added to $PATH.

git clone ./otns
cd otns

Then follow these steps to use Silk with OTNS:

  1. Configure ClusterID for the cluster. There are two ways to lay out nodes for the cluster:
    1. Specify OTNSVisPosition for each node in hwconfig.ini. Canvas is the same size in pixel as the monitor on which OTNS runs, so usually a 50px distance is clear enough.
    2. Specify LayoutCenter and LayoutRadius for the cluster in hwconfig.ini and not OTNSVisPosition. This will tell OTNS Manager to calculate each node's position dynamically based on their roles in the network.
    3. OTNS Manager will default to not using auto layout if all node's visualization positions have been set. Otherwise, it turns to auto layout.
  2. Flash each board with the images compiled with OpenThread OTNS=1 flag turned on.
  3. Run OTNS in real mode using otns -raw -real -ot-cli otns-silk-proxy.
  4. Run Silk with, supplying -s OtnsServer argument. If the server is running on the same machine, use localhost.

Using Replayer

The SilkReplayer allows offline playback of Silk log file for visualization on OTNS platform. The playback speed can be controlled via command line arguments. Usage:

usage: [-h] [-d ResPath] [-c ConfFile] [-v X] [-s OtnsServer] [-p PlaybackSpeed] P

Run a suite of Silk Tests
positional arguments:
  P                     Log file path
optional arguments:
  -h, --help            show this help message and exit
  -r ResPath, --results_dir ResPath
                        Set the path for run results. Defaults to current folder.
  -c ConfFile, --hwconfig ConfFile
                        Name the hardware config file. Defaults to `/opt/openthread_test/hwconfig.ini`.
  -v X, --verbose X, --verbosity X
                        Set the verbosity level of the console (0=quiet,
                        1=default, 2=verbose)
  -s OtnsServer, --otns OtnsServer,
                        Set the OTNS server address to send OTNS messages to. Defaults to `localhost`.
  -p PlaybackSpeed, --speed PlaybackSpeed,
                        Speed of log replay. e.g. 20 means speeding up to 20x. 1.0 by default.

There is an example of test run script under unit_tests folder.

Build Wpantund image

git clone
cd silk/silk/shell

Build OpenThread image

git clone

Please note that the openthread image should have child-supervision, mac-filter and log-output enabled (listed in detail in script

Testbed devices

To build openthread image for testbed devices and sniffer you can make use of script

cd silk/silk/shell

To utilize OTNS, OTNS=1 flag needs to be turned on when compiling the image.

With an openthread image ot-ncp-ftd.hex will be created and copied to location /opt/openthread_test/nrf52840_image/.

To flash the build on testbed device attach usb cable to j-link port and replace chip serial number printed on the chip(e.g. 683906489).

cd silk/silk/shell
./ --erase-all 683906489
./ --flash /opt/openthread_test/nrf52840_image/ot-ncp-ftd.hex 683906489

Note: On raspberry Pi JLink installed should be of the form JLink_Linux_XXX_arm.tgz and present at /opt/SEGGER. Create a symbolic link for JLink_Linux_XXX to "JLink". Make sure to run the command sudo cp 99-jlink.rules /etc/udev/rules.d/ given in README.txt of JLink and reboot the system. Example output of Jlink executable:

user@user:/opt/SEGGER$ ls -l
total 4
lrwxrwxrwx 1 root root   23 Sep 26  2018 JLink -> /opt/SEGGER/JLink_V634g
drwxr-xr-x 8 root root 4096 Aug 20 10:21 JLink_V634g

OpenThread Sniffer

nRF52840 can be used as a Thread Sniffer in Silk which can capture all 15.4 traffic in the specific wireless channel during test suite execution. The pcap file will be saved to the test result folder.

It is required that the OpenThread spinel-cli tools are installed.

git clone
cd pyspinel
sudo python develop
which (should show up in /usr/local/bin)

You now have two options.

Option 1: Add /usr/local/bin to your secure path.

Option 2: Create a symlink from a secure path location to the you found above.

Create image for sniffer

Recommend to flash the image for the Sniffer in a Linux PC.

# Prepare firmware
make -f examples/Makefile-nrf52840 USB=1
arm-none-eabi-objcopy -O ihex output/nrf52840/bin/ot-rcp ot-rcp-nrf52840-115200.hex

# Flash to device
nrfjprog -f nrf52 --chiperase --reset --program ot-rcp-nrf52840-115200.hex chip-serial-number
nrfjprog -f nrf52 --pinresetenable chip-serial-number
nrfjprog -f nrf52 --reset chip-serial-number

# Disable MSD, this is very important
cd /opt/SEGGER/JLink_XXX).
./JLinkExe -SelectEmuBySN 683906489


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