Huawei Certified Network Associate – Routing and Switching (HCNA-RS, legacy) — Question 56

Which of the following statements are true about ICMP messages? (Multiple Choice)

Answer options

• A. ICMP messages can record time, including the original time, packet receiving time, and packet sending time.
• B. ICMP messages are encapsulated in IP packets but not at the transport layer.
• C. ICMP messages include error messages, control messages, request/response messages, and update messages.
• D. ICMP does not support redirection.
• E. ICMP messages cannot be used to detect a path's MTU.

Correct answer: B, C

Explanation

Option B is correct because ICMP messages are indeed encapsulated within IP packets, and they operate at the network layer, not the transport layer. Option C is also correct as ICMP messages encompass various types, including error messages and request/response messages. The other options are incorrect because they either misstate the capabilities of ICMP or describe functions that ICMP does not perform.