Error Indications

Napatech Link™ Software Features
Platform
Intel® PAC
Napatech SmartNIC
Content Type
Feature Description
Capture Software Version
Link™ Capture Software 12.4

Frame-based error indications

These frame-based errors can be indicated in the extended packet descriptor 9:

  • Ethernet small frame error

    If the ISL, Ethernet and VLAN/MPLS/VN-Tag frame decode shows that the frame is too small for the applied protocols, an Ethernet small frame error is indicated in the frame decoder status word.

  • Ethernet large frame error

    If the frame is a large frame (see Large frames), an Ethernet large frame error is indicated for the frame. It is indicated in the frame decoder status word.

Checksum error indications

These checksum errors can be indicated for received frames on NT200A02 SmartNICs running on a test and measurement image:

  • IPv4 header checksum error

    If the packet is an IPv4 packet, and the IPv4 header checksum verification fails, an IP checksum error is indicated in the IP checksum status word. Otherwise this status word is zero.

    Note: No IP checksum exists for IPv6.

  • TCP checksum error

    If the packet is a non-fragmented IPv4 or IPv6 packet, and the TCP checksum verification fails, a TCP checksum error is indicated in the TCP checksum status word. Otherwise this status word is zero.

  • UDP checksum error

    If one of these two conditions is fulfilled, a UDP checksum error is indicated in the UDP checksum status word:
    • The packet is a non-fragmented IPv4 or IPv6 packet, the UDP checksum verification fails, and the UDP checksum differs from 0.
    • The packet is an IPv6 packet, the UDP checksum is zero, and CsrxAllowIpv6UdpZeroChecksum in the ntservice.ini file (see DN-0449) is set to false.
    Otherwise the status word is zero.

FCS error flag

A frame is flagged for FCS violation if:

  • It is smaller than 18 bytes, that is it is not a well-formed Ethernet frame and is considered a fragment.
  • It is larger than or equal to 18 bytes but smaller than or equal to 10,000, and the last 4 octets do not match the recalculated frame CRC.
  • It is larger than 10,000 bytes, that is it is a hard-sliced frame.
  • It has a code violation.
  • It has an alignment error.

FCS errors are always flagged in the standard packet descriptor (see DN-0449), but are not always counted in the statistics (see Statistics).

Hard-sliced flag

A frame is flagged for hard-slicing if the frame length is larger than 10,000 bytes.

Code violation flag

A frame is flagged for code violation if it contains code violation bit errors.