IEEE1588 PTP

Reference Documentation

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Intel® PAC
Napatech SmartNIC
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Reference Information
Napatech Software Suite: IEEE1588 PTP

IEEE1588 PTP Timesync

Using PTP as time reference (running as PTP slave to a Grand Master)

To use PTP as time reference, just add PTP in the list of clock references and the adapter will try to find a PTP Grand Master clock to synchronize time against, using the PTP ethernet port on the adapter (ip configured with DHCP). The adapter will run in default configuration and use the PTP default profile in slave-only mode. A variety of PTP configuration options are available.

PTP configuration options

The adapter implements PTP version 2 and offers a variety of configuration options. It implements the Time-of-Day synchronization method defined in the protocol. This also ensures phase synchronization and frequency synchronization, thus the frequency synchronization only mode of the PTP protocol is not selectable. It uses a PTP clock type Ordinary Clock which cannot be changed. Therefore the adapter cannot act as a Boundary Clock or as a Transparent Clock. The list of features are as follows:

  • PTP clock configuration parameters
    • Priority1
    • Priority2
    • Domain
    • Announce interval
    • Announce timeout multiplier
    • Sync interval
    • Min delay request interval
    • Min peer delay request interval
    • Communication protocol
  • PTP ethernet port configuration
    • Static IP
    • Dhcp
    • Vlan
  • PTP unicast
    PTP unicast mode may be configured. It is possible to configure up to 10 IP addresses of PTP master clocks to connect to for unicast requests. The clock implementation does combine the multicast announce messages with all the granted unicast masters announce messages to find the best master clock to select for synchronization. The adapter may also be used as unicast master.
  • PTP delay mechanism
    The adapter supports both End-to-End (delay request-response mechanism) and Peer-to-Peer (peer delay mechanism) for propagation delay measurements.
  • PTP communication protocol
    Currently supported communication protocols are IPv4/UDP and IEEE802.3 (Layer2).
  • PTP Profiles
    The adapter supports the following profiles:
    • PTP Default profile (profile Id : 00-1B-19-00-01-00)
    • Power profile (profile Id : 1C-12-9D-00-00-00)
    • Telecom profile (profile Id : 00-19-A7-00-01-00)
  • Filters
    Filters may be applied to measured values while calculating the offset from master before feed to the PI controller. This may be useful in a network with routers and/or switches with high packet delay variation (PDV). Currently, two filters are supported:
    • Minimum filter
    • Estimation filter
  • PTP master mode
    The adapter may be configured to allow PTP master mode. This involves the delivery of a PTP clock onto the PTP domain the adapter is configured to be part of. This clock will then be either free running oscillator on the adapter or an external referenced clock which the adapter is synchronized to. The clock quality description of the adapter clock used for transmitting PTP announce messages is therefore configurable. A clock class, clock accuracy and clock source may be configured for the external time source.
  • PTP management
    The PTP clock on the adapter may be managed run-time through the use of the PTP management interface defined by the IEE1588-2008 specification. This interface can be used to monitor the state and status of the adapters PTP clock. This interface also makes it possible to make configuration changes of vital PTP clock parameters at run-time. This is fully supported, however these changes cannot be stored to non-volatile memory, thus, if used, must be setup again after each reboot of the driver.