Setting Up ntpcap.ini and ntservice.ini for No Merging Between SmartNICs

libpcap Installation

product_line_custom
Intel® PAC
Napatech SmartNIC
category
Software Installation Guide

Before you begin

Note: The Inline profile does not support the PCAP packet descriptor and the PCAP-ns and PCAP-μs time stamp formats.

About this task

If merging of packets between SmartNICs is not needed, it is recommended to use the segment-based interface, as it supports the use of the PCAP packet descriptor with the PCAP-ns or PCAP-μs time stamp format.

If the standard packet descriptor is used, the time stamp conversion must be carried out in libpcap before delivering each packet to the application. Therefore the PCAP packet descriptor is faster than the standard packet descriptor.

Steps

To set up when merging packets between SmartNICs is not needed:

Procedure

  1. In the ntpcap.ini file, include the following to set up segment-based interface (default setting).
    NTInterface=Segment
  2. In the ntservice.ini file, include the following to select the PCAP packet descriptor.
    PacketDescriptor=PCAP
  3. In the ntservice.ini file, include one of the following to select the PCAP-ns or PCAP-μs time stamp format, respectively.
    • TimestampFormat=PCAP_NS
      Note: The 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. The 1 ns unit counter is incremented in quantities of 1 ns for 4GA PCIe Gen3 SmartNICs, 4 ns for 3GA PCIe Gen3 and PCIe Gen2 SmartNICs and 10 ns for 3GA PCIe Gen1 SmartNICs, so the time resolution is 1 ns, 4 ns and 10 ns, respectively, even though the unit is 1 ns. The start time is January 1st 1970.
    • TimestampFormat=PCAP
      Note: The 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.