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gPTP Sample Application


The gPTP sample application for Zephyr will enable gPTP support, registers gPTP phase discontinuity callback, enable traffic class support (TX multi queues) and setup VLANs (if enabled). The net-shell is also enabled so that user can monitor gPTP functionality.

The source code for this sample application can be found at: samples/net/gptp.


For generic host connectivity, that can be used for debugging purposes, see Networking with native_posix board for details.

Building and Running

A good way to run this sample is to run this gPTP application inside native_posix board as described in Networking with native_posix board or with embedded device like NXP FRDM-K64F or Atmel SAM-E70 Xplained. Note that gPTP is only supported for boards that have an Ethernet port and which has support for collecting timestamps for sent and received Ethernet frames.

Follow these steps to build the gPTP sample application:

west build -b <board to use> samples/net/gptp

The net-shell command “net gptp” will print out general gPTP information. For port 1, the command “net gptp 1” will print detailed information about port 1 statistics etc. Note that executing the shell command could affect the timing of the sent or received gPTP packets and the grandmaster might mark the device as non AS capable and disable it.

Setting up Linux Host

If you need VLAN support in your network, then the samples/net/vlan/ provides a script that can be executed on the Linux host. It creates two VLANs on the Linux host and creates routes to Zephyr. If you are using native_posix board, then the will create VLAN setup automatically with this command:

./ -c zeth-vlan.conf

The OpenAVNU repository at contains gPTP daemon that can be run in Linux host and which can act as a grandmaster for the IEEE 801.1AS network. Note that OpenAVNU will not work with native_posix board as that board only supports software timestamping and OpenAVNU only supports hardware timestamping. See instructions at the end of this chapter how to run linuxptp daemon with native_posix board.

Get OpenAvnu/gPTP project sources

git clone

After downloading the source code, compile it like this in Linux:

mkdir build
cd build
cmake ..
cp ../gptp_cfg.ini .

Edit the gptp_cfg.ini file and set the neighborPropDelayThresh to 10000 as the default value 800 is too low if you run the gPTP in FRDM-K64F.

Then execute the daemon with correct network interface and the configuration file.

sudo ./gptp enp0s25 -F gptp_cfg.ini

Note that here the example network interface enp0s25 is the name of the network interface that is connected to your Zephyr device.

If everything is configured correctly, you should see following kind of messages from gptp:

INFO     : GPTP [13:01:14:837] gPTP starting
INFO     : GPTP [13:01:14:838] priority1 = 248
INFO     : GPTP [13:01:14:838] announceReceiptTimeout: 3
INFO     : GPTP [13:01:14:838] syncReceiptTimeout: 3
INFO     : GPTP [13:01:14:838] LINKSPEED_100MB - PHY delay
                    TX: 1044 | RX: 2133
INFO     : GPTP [13:01:14:838] LINKSPEED_1G - PHY delay
                    TX: 184 | RX: 382
INFO     : GPTP [13:01:14:838] neighborPropDelayThresh: 10000
INFO     : GPTP [13:01:14:838] syncReceiptThreshold: 8
ERROR    : GPTP [13:01:14:838] Using clock device: /dev/ptp0
STATUS   : GPTP [13:01:14:838] Starting PDelay
STATUS   : GPTP [13:01:14:838] Link Speed: 1000000 kb/sec
STATUS   : GPTP [13:01:14:871] AsCapable: Enabled
STATUS   : GPTP [13:01:16:497] New Grandmaster "3C:97:0E:FF:FE:23:F2:32" (previous "00:00:00:00:00:00:00:00")
STATUS   : GPTP [13:01:16:497] Switching to Master

If Zephyr syncs properly with gptp daemon, then this is printed:

STATUS   : GPTP [13:01:25:965] AsCapable: Enabled

By default gPTP in Zephyr will not print any gPTP debug messages to console. One can enable debug prints by setting CONFIG_NET_GPTP_LOG_LEVEL_DBG in the config file.

For native_posix board, use linuxptp project as that supports software timestamping.

Get linuxptp project sources

git clone git://

Compile the ptp4l daemon and start it like this:

sudo ./ptp4l -2 -f gPTP-zephyr.cfg -i zeth -m -q -l 6 -S

Use the default.cfg as a base, copy it to gPTP-zephyr.cfg, and modify it according to your needs.

Multiport Setup

If you set CONFIG_NET_GPTP_NUM_PORTS larger than 1, then gPTP sample will create multiple TSN ports. This configuration is currently only supported in native_posix board.

You need to enable the ports in the net-tools. If the number of ports is set to 2, then give following commands to create the network interfaces in host side:

sudo ./ -c zeth0-gptp.conf -i zeth0 start
sudo ./ -c zeth1-gptp.conf -i zeth1 start

After that you can start ptp4l daemon for both interfaces. Please use two terminals when starting ptp4l daemon. Note that you must use ptp4l as OpenAVNU does not work with software clock available in native_posix.

cd <ptp4l directory>
sudo ./ptp4l -2 -f gPTP-zephyr.cfg -m -q -l 6 -S -i zeth0
sudo ./ptp4l -2 -f gPTP-zephyr.cfg -m -q -l 6 -S -i zeth1

Compile Zephyr application.

west build -b native_posix samples/net/gptp

When the Zephyr image is build, you can start it like this:

build/zephyr/zephyr.exe -attach_uart