ISC Exam Questions

Which of the following layers of the OSI model are tested through this process?

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.

A.
Layer 3

B.
Layer 2

C.
Layer 4

D.
Layer 1

Explanation:
The PING command uses the Internet Control Message Protocol (ICMP) for sending a
message called ICMP echo request to a host to which
the connectivity is to be tested. The remote host replies with an ICMP echo message. The successful
completion of this process shows that
the IP network is working properly. ICMP does not rely on any application and hence tests only the
basic IP connectivity through layers 1, 2,
and 3 (i.e. the Physical, Data link, and Network layers).