Cisco Certified Network Associate (CCNA) Practice Exam

When reconnecting a switch to a network, what factor determines if it will replace the current VLAN database?

1. VLAN ID

2. Switch model

3. VTP revision number

4. Switch IP address

The correct answer is: VTP revision number

When reconnecting a switch to a network, the VTP (VLAN Trunking Protocol) revision number is the factor that determines whether the switch will replace the current VLAN database. VTP is designed to manage VLAN information across a network of switches by propagating VLAN configuration changes. Each time a VLAN configuration is modified on a switch that is participating in VTP, the VTP revision number is incremented. When a switch joins a VTP domain, it sends out its VTP advertisements containing its revision number. If the connecting switch has a higher VTP revision number than the existing switches in the network, it indicates that it has more recent VLAN information, and as a result, it will overwrite the VLAN database of the existing switches with its own configuration. In contrast, other factors such as VLAN ID, switch model, and switch IP address are not relevant to determining whether VLAN database replacement occurs. VLAN ID only identifies specific VLANs without impacting the database integrity, while switch model variations do not affect VTP operations. Switch IP addresses facilitate communication but do not play a role in the VTP database synchronization or the determination of which VLAN database takes precedence.