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

Napatech Link-Capture™ Software and WinPcap-NT Installation Guide for Windows

Platform
Napatech SmartNIC
Content Type
Software Installation Guide
Capture Software Version
Link™ Capture Software 12.11

Before you begin

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 WinPcap before delivering each packet to the application. Therefore the PCAP packet descriptor is faster than the standard packet descriptor.

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. 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.