A host needs to transmit a 9000-byte IPv4 datagram, including a 20-byte header, across a link with MTU = 2500 bytes. The DF (Don't Fragment) bit is not set, and the fragment offset is in units of 8 bytes.

Step 1: Determine Payload Per Fragment

Each fragment must include a 20-byte header, so the maximum data payload per fragment is:

MTU - IP header = 2500 - 20 = 2480 bytes

The total payload in the datagram is:

9000 - 20 = 8980 bytes

Step 2: Calculate Number of Fragments

Divide total payload by payload per fragment:

8980 ÷ 2480 ≈ 3.62

• 3 full fragments of 2480 bytes

• 1 last fragment carries 8980 - (2480 × 3) = 1540 bytes

So, total fragments = 4.

Step 3: Calculate Fragment Offsets

Offsets are measured in units of 8 bytes:

Step 4: Set MF (More Fragments) Flag

• MF = 1 for all fragments except the last one.

• MF = 0 for the last fragment.

Step 5: Total Length for Each Fragment

Add 20-byte header to each fragment payload: