CompTIA Security+ (SY0-501) — Question 1017

A consultant has been tasked to assess a client's network. The client reports frequent network outages. Upon viewing the spanning tree configuration, the consultant notices that an old and law performing edge switch on the network has been elected to be the root bridge.
Which of the following explains this scenario?

Answer options

• A. The switch also serves as the DHCP server
• B. The switch has the lowest MAC address
• C. The switch has spanning tree loop protection enabled
• D. The switch has the fastest uplink port

Correct answer: B

Explanation

The correct answer is B because the spanning tree protocol elects the root bridge based on the lowest bridge ID, which is determined by the combination of the bridge priority and the MAC address; hence the switch with the lowest MAC address is elected. Options A, C, and D are incorrect because they do not influence the selection of the root bridge in a spanning tree configuration.