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
WinPcap before delivering each
packet to the application. Therefore the PCAP packet descriptor is faster than the standard
packet descriptor.
Procedure
-
In the ntpcap.ini file, include the following to set up
segment-based interface (default setting).
-
In the ntservice.ini file, include the following to select the
PCAP packet descriptor.
-
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.