VTP primary server
When configuring VTP version 3, in order to be able to create and modify VLAN configurations, a switch must be the primary VTP server. If it is not configured as the primary VTP server, the following error will be displayed if a change in the configured VLANs is attempted:
SW2(config)#vlan 501 VTP VLAN configuration not allowed when device is not the primary server for vlan database. SW2(config)#
To set a switch as the primary server, use the following command in global configuration mode:
SW2#vtp primary
Once initiated, the switch will search for any conflicting VTP3 devices. If no conflicts are found, you are asked to confirm the change. The following shows the sequence of events:
SW2#vtp primary This system is becoming primary server for feature vlan No conflicting VTP3 devices found. Do you want to continue? [confirm] SW2# *Jun 13 06:21:51.477: %SW_VLAN-4-VTP_PRIMARY_SERVER_CHG: 5254.0000.8000 has become the primary server for the VLAN VTP feature
Links
https://networklessons.com/switching/private-vlan-pvlan-cisco-catalyst-switch