Time Stamp Formats

Time-Stamping and Time Synchronization

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Intel® PAC
Napatech SmartNIC
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User Guide

In this section

This section describes the different time stamp formats supported by the SmartNICs. The formats have different start times. Configuration of the SmartNICs with respect to time stamp formats is described in Specifying the Time Stamp Format.

Native UNIX format

Native UNIX format is based on a 10 ns unit with a 64-bit unit counter. The start time is January 1st 1970. This is the default format for the SmartNICs.

Native UNIX ns format

Native UNIX ns format is based on a 1 ns unit with a 64-bit unit counter. The start time is January 1st 1970.
Note: Native UNIX ns format does not apply to NT40A01-4×10/1-SLB.

PCAP-μs format

PCAP-μs format is based on a 1000 ns (1 μs) unit with a 32-bit unit counter in MSBs of the time stamp descriptor field, and a 32-bit second counter in LSBs of the time stamp descriptor field. The start time is January 1st 1970.
Note: PCAP-μs format can only be used if PCAP packet descriptor is selected for all SmartNICs.

PCAP-ns format

PCAP-ns format is based on a 1 ns unit with a 32-bit unit counter in MSBs of the time stamp descriptor field, and a 32-bit second counter in LSBs of the time stamp descriptor field, so the time resolution is 1 ns. The start time is January 1st 1970.
Note: PCAP-ns format can only be used if PCAP packet descriptor is selected for all SmartNICs.

Format limitations

The internal SmartNIC time, time offset and time stamp format are global settings for the SmartNIC, so all received frames use the same time source and format.

PCAP-ns or PCAP-μs format can only be used if the PCAP packet descriptor is selected for all SmartNICs (see DN-1128).