Packet Masking

Napatech Link-Capture™ Software Features

Intel® PAC
Napatech SmartNIC
Content Type
Feature Description
Capture Software Version
Link™ Capture Software 12.9


A specific part of a frame can be masked out by zeroing the configured fields. The following NTPL example configures the SmartNIC to mask out 16 bytes in the layer 4 payload of a frame.
Define maskRecipe = Mask(Offset0=Layer4Payload[0], Length0=16)
Assign[StreamId=0;Mask=maskRecipe] = Layer4Protocol==TCP
Two elements are used to configure the field for packet masking.
  • Offset0=Layer4Payload[0]: The starting byte which is specified using a dynamic offset and a static offset where a dynamic offset is based on a predefined protocol layer, and a static offset is relative to the dynamic offset. In this example, Layer4Payload is the dynamic offset and [0] is the static offset. The starting byte is byte 0 of the layer 4 payload.
    Note: Supported static offset values are -16384 to 16383.
  • Length0=16: The length of the field in bytes. A maximum of 16 bytes can be configured.
A maximum of 4 fields are supported as follows.
Define maskRecipe = Mask(Offset0=StartOfFrame[0], Length0=16, Offset1=StartOfFrame[32], Length1=16, \\
Offset2=StartOfFrame[64], Length2=16, Offset3=StartOfFrame[96], Length2=16)
Assign[StreamId=0;Mask=maskRecipe] = Port==0
Note: Packet masking only applies to the following SmartNICs.
  • NT200A02 running on a capture/replay image
  • NT100A01 running on a test and measurement image