Cisco Certified Network Associate (CCNA) Practice Exam

What command is used to display VLAN specific spanning tree information?

1. show spanning-tree

2. show vlan

3. show spanning-tree vlan VLAN NUMBER

4. show interfaces

The correct answer is: show spanning-tree vlan VLAN NUMBER

The command used to display VLAN-specific spanning tree information is "show spanning-tree vlan VLAN NUMBER." This command provides detailed information about the spanning tree protocol (STP) related to a specific VLAN. When you include the VLAN number, the command retrieves and presents the STP state and details solely for that particular VLAN, including parameters such as the root bridge, which port is in the forwarding or blocking state, and any other pertinent information that helps in diagnosing or managing the Ethernet configuration for that VLAN. Using this command is essential for network administrators who need to understand the topology and performance of a VLAN within the network. It helps track the health of the network segments and the STP configurations that could affect overall network efficiency and loop prevention. The other choices do not specifically focus on VLANs. "Show spanning-tree" provides a broader view of the spanning tree information across all VLANs without isolating the details for a particular VLAN. "Show vlan" focuses on VLAN configuration information but does not include spanning tree details. "Show interfaces" presents details about the interfaces on a switch or router, such as link status and speed, but does not provide information specific to spanning tree protocol for VLANs.