CCNA Practice Exam Test Sample – Question 35

Which two protocols are used by bridges and/or switches to prevent loops in a layer 2 network? (Choose two.)

A. 802.1d
B. VTP
C. 802.1q
D. STP
E. SAP

Correct Answers: A,D
Section: LAN Switching Technologies

Explanation:
This question is to examine the STP protocol.
STP (802.1d) is used to prevent Layer 2 loops.
802.1q is a Frame Relay protocol which belongs to VLAN.
SAP is a concept of the OSI model.