PTP Profiles Guide

This guide provides instructions on setting the Precision Time Protocol (PTP) profile of the Ouster sensor. The profile of the Ouster sensor and your master clock must match for time synchronization to be possible.

PTP Profiles

There are several PTP profiles that are commonly used. The supported profiles on the Ouster sensor are listed below:

  • default - The IEEE 1588 Default PTP profile addresses many common applications. Most PTP capable devices support the Default profile.

  • gptp - Generalized PTP (gPTP) is the common name for the IEEE standard 802.1AS-2011 which improves the interoperability of PTP by simplifying the supported options. The gPTP profile is useful when using the Ouster sensor with gPTP compatible hardware such as an Audio Visual Bridge (AVB), e.g. the MOTU AVB.

  • automotive-slave - The Automotive Slave PTP profile is commonly used in automotive applications. The primary differences from other profiles are that the Best Master Clock Algorithm (BMCA) is disabled, the slave device inhibits announce messages, and the time convergence controller is approximately 8 times faster than the Default profile.

PTP HTTP API

The PTP profile of the sensor is changed using an HTTP PUT request. This can be done using several different tools such as httpie, curl, Advanced REST Client, etc. The full API is available in GET /api/v1/time/ptp/profile.

  • The request URL is: http://<sensor_hostname>/api/v1/time/ptp/profile/

  • Valid values are (““, are included):

    • “default”

    • “gptp”

    • “automotive-slave”

Note

Changing the PTP profile does not require reinitialization or writing the configuration text file to be persistent. It is persistent as soon a valid PUT request is executed and a valid response is received.

Enabling the PTP profiles

Below are some examples using popular command-line tools.

Example using cURL

In this example we are setting the PTP profile of the Ouster sensor to "gptp" using the cURL command line tool.

  • Command

    curl -X PUT -H "Content-Type: application/json" -d '"gptp"' http://<sensor_hostname>/api/v1/time/ptp/profile/

  • Response

    "gptp"%

Example using Httpie

In this example we are setting the PTP profile of the Ouster sensor to "default" using the Httpie command line tool.

  • Command

    http PUT http://<sensor_hostname>/api/v1/time/ptp/profile <<< '"default"'

  • Response

    "default"%

Sync Verification

Please see the Sensor PTP Sync Verification section for details on how to verify the sensor is synchronized.