Refer to the exhibit.
If CDP is enabled on all devices and interfaces, which devices will appear in the output of a show
cdp neighbors command issued from R2?
A.
R2 and R3
B.
R1 and R3
C.
R3 and S2
D.
R1, S1, S2, and R3
E.
R1, S1, S2, R3, and S3
Explanation:
A Cisco device enabled with CDP sends out periodic interface updates to a
multicast address in order to make itself known to neighbors. Since it is a layer two protocol, these
packets are not routed. So the devices detected would be immediate connected neighbors.
Since CDP is a L2 protocol, why answer D (R1,S1,S2, and R3) can’t be correct?
Because R1, S1 are not directly connected. S2 $ R3 are directly connected.
R2#show cdp neighbors (work only for cisco devices that are directly connected)