A primary server is the single VTP version 3 switch in a domain authorized to create, modify, and delete VLANs. Other VTP servers become secondary servers and function like VTP clients. This restriction prevents a newly connected switch from overwriting the domain’s VLAN database. section 13.2.3 section 13.2.4
Remember these operational rules:
- Enable VTP version 3 before using primary-server control. section 13.2.3
- Use vtp primary in privileged EXEC mode; from global configuration mode, prefix it with do. section 13.2.3
- Only one switch can be primary. Making a second switch primary changes the first switch to secondary. section 13.2.3
- Synchronize VTP version 3 switches only with the primary server, reducing the higher-revision-number overwrite problem. section 13.2.4
Making SW1 primary
SW1(config)# vtp version 3 SW1(config)# vlan 6 VTP VLAN configuration not allowed when device is not the primary server for vlan database. SW1(config)# do vtp primary This system is becoming primary server for feature vlan SW1(config)# vlan 6 SW1(config-vlan)# exit The first VLAN command fails because SW1 is not primary. After do vtp primary, SW1 can create VLAN 6. section 13.2.3
SW1(config)# vtp version 3 #1 SW1(config)# vlan 6 #2 VTP VLAN configuration not allowed when device is not the primary server for vlan database. #3 SW1(config)# do vtp primary #4 This system is becoming primary server for feature vlan #4 No conflicting VTP3 devices found. #4 Do you want to continue? [confirm] #4 SW1(config)# vlan 6 #5 SW1(config-vlan)# exit #5 #1 Enables VTP version 3 #2 Creates a VLAN #3 The command is rejected. #4 Makes SW1 the primary server #5 SW1 can now create VLANs.
Use the annotated CLI listing to distinguish enabling VTP version 3, the rejected VLAN command, the privileged primary-server command, and the successful retry. section 13.2.3
