A packet has arrived with an M bit value of 0. Is this the first fragment, the last fragment or a middle fragment? Do you know if the packet was fragmented?

You’re given a packet where the M bit (More Fragments flag) = 0. 

Now the question is simple but important. What does that actually tell you?

Let’s think it through carefully.

The M bit tells you whether more fragments are coming after this packet.
If M = 1, it means more fragments are still on the way.
If M = 0, it means this is the last fragment in the sequence or the only packet if no fragmentation happened.

So with M = 0, two possibilities exist.
It could be the last fragment of a fragmented packet, or it could be a complete packet that was never fragmented.

Now here’s the key point.
From the M bit alone, you cannot confirm whether fragmentation actually happened.

To know that, you also need the fragment offset.

• If the offset = 0 and M = 0, then it means no fragmentation happened.
• If the offset > 0 and M = 0, then it is definitely the last fragment.

Final Interpretation

• M = 0 does not always mean “not fragmented”

• It only tells you that no more fragments follow

• You need the offset field to confirm the full situation

Result

Case	M Bit	Fragment Offset	Interpretation	Was Fragmented?
Case 1	0	0	Single packet (not fragmented)	No
Case 2	0	> 0	Last fragment	Yes