How do I calculate the fragment offset

Hi Sprout,

The fragment offset is the relative position of a fragment in the original packet. The offset unit is 8 bytes. That is, the length of each fragment must be an integral multiple of 8 bytes (64 bits). 

A total of 3800 bytes need to be transmitted, and a maximum of 1400 bytes can be transmitted at a time (because 20 bytes of the fixed IP header need to be added, the MTU=1420 bytes). Therefore, only three times of transmission are required, that is, 1400 bytes + 1400 bytes + 1000 bytes (3800 bytes in total). 

In this way, the fragment offset is 0 during the first transmission. For the second transmission, the offset is 175 (1400/8). For the third transmission, the fragment offset is 2800/8 = 350.