IP datagram has arrived with following partial information in the header (in…

Concept

An IPv4 header packs a 4-bit Version field and a 4-bit IHL (Internet Header Length) field into its first byte. IHL states the header size in 32-bit (4-byte) words, and the following 16-bit Total Length field states the entire datagram size in bytes.

Payload (useful data) = Total Length − Header Length, and the transmission efficiency of the datagram = (Payload ÷ Total Length) × 100.

Application

1. First byte = 45 (hex) = 0100 0101 (binary): Version = 0100 = 4, IHL = 0101 = 5.

2. Header Length = IHL × 4 bytes = 5 × 4 = 20 bytes.

3. Total Length field (next two bytes) = 00 54 (hex) = 0x54 = 84 (decimal).

4. Payload = Total Length − Header Length = 84 − 20 = 64 bytes.

5. Efficiency = (Payload ÷ Total Length) × 100 = (64 ÷ 84) × 100 ≈ 76.19%.

Cross-check

Header share of the datagram = 100% − 76.19% = 23.81%, i.e. 20 ÷ 84 × 100 ≈ 23.81%. The header and payload shares add back to 20 + 64 = 84 bytes, matching the Total Length field, which confirms the split.

Final Answer:

Efficiency of the datagram ≈ 76.19% (≈ 76%).