In the IPv4 header, what do the MF flag and Fragment Offset field indicate?

• A. MF indicates if more fragments follow; Fragment Offset specifies the fragment's position in the original datagram (in 8-byte units).
• B. MF indicates final fragment; Offset is in bytes.
• C. MF marks the payload as urgent; Offset is in bits.
• D. MF indicates payload length; Offset shows sequence number.

Answer: (A)

In IPv4 fragmentation, two fields tell the receiver how to reassemble pieces of a larger datagram: the More Fragments flag and the Fragment Offset. The More Fragments flag indicates whether more fragments follow this one. If more fragments do follow, the flag is set to 1; the final fragment has this flag set to 0. The Fragment Offset shows where this fragment’s data starts within the original datagram and is measured in 8-byte units. The first fragment has an offset of 0, and each subsequent fragment’s offset increases by the length of the previous fragment’s data divided by 8. This combination lets the destination stitch all fragments back together in the correct order. The offset is not in bytes or bits, and MF is not about payload length or urgency.