CISSP-ISSAP · Question #128
You work as a Network Administrator for McRoberts Inc. You are expanding your company's network. After you have implemented the network, you test the connectivity to a remote host by using the PING co
The correct answer is A. Layer 3 B. Layer 2 D. Layer 1. PING uses ICMP, which operates at Layer 3 (Network) - making Layer 3 correct because IP addressing and routing must function for the echo request/reply to traverse the network. Layers 1 (Physical) and 2 (Data Link) are implicitly tested because data cannot traverse the network wi
Question
You work as a Network Administrator for McRoberts Inc. You are expanding your company's network. After you have implemented the network, you test the connectivity to a remote host by using the PING command. You get the ICMP echo reply message from the remote host. Which of the following layers of the OSI model are tested through this process? Each correct answer represents a complete solution. Choose all that apply.
Options
- ALayer 3
- BLayer 2
- CLayer 4
- DLayer 1
How the community answered
(58 responses)- A74% (43)
- C26% (15)
Explanation
PING uses ICMP, which operates at Layer 3 (Network) - making Layer 3 correct because IP addressing and routing must function for the echo request/reply to traverse the network. Layers 1 (Physical) and 2 (Data Link) are implicitly tested because data cannot traverse the network without a working physical medium and data link framing (Ethernet, MAC addressing, ARP) functioning correctly end-to-end. Layer 4 (Transport) is the distractor - ICMP is encapsulated directly inside IP at Layer 3 and does not use TCP or UDP, so no transport-layer functionality is exercised.
Memory tip: "PING checks the bottom three layers - Physical wire, Data link frame, Network packet (1-2-3). It skips Layer 4 because ICMP has no port numbers and needs no transport protocol."
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