VTP - Should we use it?

VLAN Trunking Protocol: most commands can be configured in PRIVILEGED, CONFIGURE or DATABASE mode

- Have in mind that there is no way to dis-configure the VTP DOMAIN NAME (by default its NULL). You have to delete flash:vlan.dat and erase the Startup config and reload the router

VTP messages source IP (the IP from which the VTP messages are sourced):
(config)#vtp interface Loopback 1 [only] <- It will not be propagated

Restrict FLOOD TRAFFIC to the TRUNK Interfaces - use VTP PRUNING>
There are 4 types of VTP Advertisments exchanged between the switches:
1. Summary Advertisments - every time VTP database changes (every 300 ms)
2. Subset Advertisments - sent right after SUMMARY, includes what exactly changed
3. Advertisments requested from clients - client requests info to update the VTP database, server responds
4. VTP Membership announcements - when PRUNING is enabled, they tell the neighbor WHAT VLANs they want (if the VLAN is not announced with this message, it is not on the trunk)

Check the PRUNING STATUS:
#show interfaces pruning
Pruning not currently enabled in this device's VTP administrative domain.

ENABLE PRUNING>
#vtp pruning <--- PROPAGATED TO ALL SWITCHES WITHIN THE VTP DOMAIN
Pruning switched on

*VLAN 1 CANNOT BE PRUNED!!!
**VLANs that are used locally also CANNOT BE PRUNED