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An IP router with a Maximum Transmission Unit (MTU) of 1500 bytes has received an IP packet of size 4404 bytes with an IP header of length 20 bytes. The values of the relevant fields in the header of the third IP fragment generated by the router for this packet are

1. MF bit: 0; Datagram Length: 1444; Offset: 370
2. MF bit: 1; Datagram Length: 1424; Offset: 185
3. MF bit: 1; Datagram Length: 1500; Offset: 370
4. MF bit: 0; Datagram Length: 1424; Offset: 2960

Correct answer: MF bit: 0; Datagram Length: 1444; Offset: 370

Solution

Payload = 4404 - 20 = 4384 bytes, split into 1480 + 1480 + 1424. The third fragment carries 1424 data bytes, total length 1424 + 20 = 1444, byte offset 2960 so fragment offset 2960/8 = 370, and MF = 0 since it is last. That is option (A), not the stored option.

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