GATE CS 2025 Set 2 Q.16: IPv4/IPv6 Addressing, Subnetting, CIDR, ARP, ICMP and NAT

Consider the following statements:

(i) Address Resolution Protocol (ARP) provides a mapping from an IP address to the corresponding hardware (link-layer) address.
(ii) A single TCP segment from a sender S to a receiver R cannot carry both data from S to R and acknowledgement for a segment from R to S.

Which ONE of the following is CORRECT?

Both (i) and (ii) are TRUE

(i) is TRUE and (ii) is FALSE

(i) is FALSE and (ii) is TRUE

Both (i) and (ii) are FALSE

Official answer and solution

Solution

Verify the purpose of ARP (statement i) and TCP piggybacked acknowledgements (statement ii).

Statement (i) is TRUE: ARP resolves a known IPv4 address within a local subnet to its corresponding 48-bit MAC (hardware/link-layer) address.
Statement (ii) is FALSE: TCP supports piggybacking, where a single TCP segment from $S$ to $R$ carries data payload from $S$ to $R$ while simultaneously setting the ACK control bit and Acknowledgment Number field to acknowledge bytes received from $R$ .

Final answer

Option (B)

The answer is the one in the official GATE answer key. The solution is this site's own explanation.

Paper: GATE 2025 Computer Science and Information Technology - Session 2 (CS2)
Question: 16 of 65
Section: Computer Science and Information Technology

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