When connecting a new switch to your network you can accidentally change your current VLAN database if the new switch has a higher VLAN Trunking Protocol (VTP) revision number. To avoid this, you must clear the VTP revision number on the new switch. The easiest way is to change the VTP domain name to “something_else” and back to “your_VTP_domain” on the new switch. This sets the VTP revision number to 0 and you can connect the switch to the network without any problem.
May 23, 2006
Connecting a new switch