IP datagram has arrived with following partial information in the header (in…
2023
IP datagram has arrived with following partial information in the header (in hexadecimal)
45000054000300002006……
What is the protocol of the payload being carried by the packet?
- A.
ICMP
- B.
SCTP
- C.
TCP Protocol
- D.
IGMP
Attempted by 186 students.
Show answer & explanation
Correct answer: C
Step 1: Write the header bytes in sequence45 00 00 54 00 03 00 00 20 06 …
Step 2: Recall IPv4 Header Format (Initial Fields)
Byte Position | Field |
|---|---|
1st byte | Version + IHL |
2nd byte | Type of Service |
3rd–4th bytes | Total Length |
5th–6th bytes | Identification |
7th–8th bytes | Flags + Fragment Offset |
9th byte | Time To Live (TTL) |
10th byte | Protocol |
Step 3: Identify the Protocol Field
From the header:
45 | 00 | 00 54 | 00 03 | 00 00 | 20 | 06
So,
Protocol field = 06 (Hexadecimal)
Step 4: Convert Protocol Number to Meaning
In IPv4, protocol numbers are standardized:
Protocol Number (Hex) | Decimal | Protocol Name |
|---|---|---|
01 | 1 | ICMP |
06 | 6 | TCP |
11 | 17 | UDP |
Here,
06 (Hex) = 6 (Decimal)
Protocol number 6 corresponds to TCP (Transmission Control Protocol).
Final Answer:
The payload is carrying TCP (Transmission Control Protocol).
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