VTP notes

• In VTP v1 & v2 change mode to transparent to reset revision number
• Vlan state(Active/Suspended) is advertised by VTP. Shutting down a vlan is locally significant to the device the the command was applied
• A transparent switch forwards VTP packets only if they match it's own configured VTP domain
• DTP negotiation between two switches requires VTP domain name to match between switches
• If a switch doesn't receive a VTP pruning response on a port, as a fallback mechanism, it doesn't prune any vlan on that port. As a consequence it requests all vlans from it VTP neighbors, which actually cancels VTP pruning operation. This is true for edge ports too. As a solution either disable VTP on that port(VTPv3) or manually set allowed vlan list. 
• Don't use VTP pruning on a VTP domain that includes transparent switches. Transparent switches only forward VTP packets and don't take part in the negotiation, leading to traffic blackholes
• By default all standard vlans are included in the prune eligible list
• VTP domain name is case sensitive
• In transparent mode vlans are stored in running config
• In client/server mode vlans are stored in vlan database
• In VTPv3 you have to define a primary server in exec mode in order to be able to alter the vlan database
• In VTPv3 you need to disable VTP pruning in order to advertise the extended vlan range
• Useful debug command: debug sw-vlan vtp events