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Spirent TestCenter: How to send IPv4 fragments with raw streamblock?

Environment/Versions
  • Spirent TestCenter
  • IP Fragmentation using Raw streamblocks
Answer
  •  When trying to send fragment packets, the "fragment offset" value should be right, or else DUT or wireshark can't reassemble the packets.‚Äč
    • The unit of "Fragment offset" is 8 bytes.
  • So if the frame length of each fragment is 1514(without FCS), the data length in the IP packet is 1514 - 14(Ethernet Header) - 20(IP Header) =1480
    • "Fragment offset" of the second fragment should be 1480/8 = 185
  • So the value of "Fragment offset" be set in the STC should be 185 (For second fragment), 370(For the third fragment) and so on
  • Note :  All fragments must have the same Identification field value in the IP Header.
  • Click here for sample video

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