nerdexam
Cisco

200-301 · Question #1543

Refer to the exhibit. Which switch in this configuration will be elected as the root bridge? SW1: 0C:E4:82:33:62:23 SW2: 0C:0E:16:11:05:97 SW3: 0C:E0:16:1A:3C:9D SW4: 0C:00:18:A1:B3:19

The correct answer is B. SW2. The root bridge in an STP domain is elected based on the lowest Bridge ID, which combines bridge priority and MAC address.

Submitted by suresh_in· Mar 5, 2026Network Access

Question

Refer to the exhibit. Which switch in this configuration will be elected as the root bridge? SW1: 0C:E4:82:33:62:23 SW2: 0C:0E:16:11:05:97 SW3: 0C:E0:16:1A:3C:9D SW4: 0C:00:18:A1:B3:19

Exhibits

200-301 question #1543 exhibit 1
200-301 question #1543 exhibit 2

Options

  • ASW1
  • BSW2
  • CSW3
  • DSW4

How the community answered

(52 responses)
  • A
    6% (3)
  • B
    73% (38)
  • C
    17% (9)
  • D
    4% (2)

Why each option

The root bridge in an STP domain is elected based on the lowest Bridge ID, which combines bridge priority and MAC address.

ASW1

SW1's MAC address (0C:E4:82:33:62:23) is numerically higher than SW2's, so it would not be elected root with default priorities.

BSW2Correct

In Spanning Tree Protocol, the root bridge is elected based on the lowest Bridge ID. While not explicitly stated with default priorities, for SW2 to be elected as the root bridge over SW4 which has a numerically lower MAC address, SW2 must possess the lowest Bridge ID, typically achieved by configuring a lower Bridge Priority value than the other switches in the network.

CSW3

SW3's MAC address (0C:E0:16:1A:3C:9D) is numerically higher than SW2's, so it would not be elected root with default priorities.

DSW4

SW4's MAC address (0C:00:18:A1:B3:19) is numerically lower than SW2's, meaning it would be the root if all switches had default priorities, but given B is the correct answer, SW4's Bridge ID must be higher (e.g., due to a higher priority).

Concept tested: Spanning Tree Protocol (STP) Root Bridge Election

Source: https://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/10556-16.html

Topics

#STP#root bridge election#MAC address comparison

Community Discussion

No community discussion yet for this question.

Full 200-301 Practice