Command
VTP Pruning
Use
VTP pruning spares bandwidth and adds to security by paying attention to what switches have interfaces assigned to VLANs. If a switch isn’t using a particular VLAN, the VTP server will block traffic from the VLAN going to that switch.
Syntax
Swtich(config)#vtp pruning
Example

In the below example we will turn on VTP pruing on SW1. On SW2 we can see that Fa0/9 and Fa0/12 are in VLAN 11.
SW2(config)#do show vlan brief VLAN Name Status Ports |
We then turn switchin on for SW1. Looking at the show interface trunk output, we can see that Fa0/23 is allowing VLAN11 traffic.
SW1(config)#vtp pruning SW1#conf t Port Mode Encapsulation Status Native vlan Port Vlans allowed on trunk Port Vlans allowed and active in management domain Port Vlans allowed and active in management domain Port Vlans in spanning tree forwarding state and not pruned |
Checking show cdp neighbor on SW1, we see that Fa0/23 is connected to SW2.
SW1(config)#do show cdp neighbor Device ID Local Intrfce Holdtme Capability Platform Port ID |