What is the second method to reset the VTP revision number to 0?

To reset the Virtual Trunking Protocol (VTP) revision number to 0, changing the VTP domain to an unused domain is a valid method. VTP uses the revision number to manage VLAN configurations within a VTP domain, and when you switch to a new, unused domain, it resets the revision number for that particular switch. This effectively starts the VTP configuration fresh, ensuring that there are no conflicting or outdated VLAN details from the previous domain.

In this context, disabling VTP would stop VTP operations but would not reset the revision number to 0; it would simply cease VTP functionality. Switching to Layer 3 mode does not directly impact the VTP domain or its revision number, as VTP is a Layer 2 protocol. Increasing the VLAN range does not inherently affect the revision number; rather, it pertains to the number of VLANs that can be configured and managed. Each of these options addresses different aspects of VTP and its operation but does not achieve the same result as changing to an unused domain.