In IPv4 fragmentation, what do MF and the Fragment Offset fields indicate?

• A. MF indicates more fragments follow; Fragment Offset shows each fragment's starting position in the original payload.
• B. Fragment Offset shows the starting position; MF marks the fragmentation ID.
• C. MF indicates final fragment; Fragment Offset determines the total payload length.
• D. MF signals the destination port; Fragment Offset shows time-to-live.

Answer: (A)

During IPv4 fragmentation, each fragment carries header fields that help the destination reconstruct the original datagram. The MF (More Fragments) flag tells the reassembler whether there are more fragments after this one. It is set to 1 for every fragment except the last, which has MF = 0 to indicate there are no more fragments. The Fragment Offset field indicates where this fragment’s data begins within the original payload, measured in 8-byte units. For example, an offset of 0 means the fragment starts at byte 0 of the original datagram, while an offset of 2 means it starts at byte 16. The destination uses these offsets to place fragments in the correct order and then concatenates their data to recover the full original payload.