VLAN Trunking Protocol (VTP) Pruning is a feature in Cisco switches that helps to reduce the amount of broadcast and multicast traffic that is sent over a VLAN trunk.

VTP Pruning works by marking certain VLANs as inactive on a trunk link, meaning that the switch will not forward any broadcast or multicast traffic for those VLANs over the trunk. This helps to reduce the amount of unnecessary network traffic and improve network performance.

When VTP Pruning is enabled, a switch will only forward broadcast and multicast traffic for active VLANs over the trunk. If a switch receives a broadcast or multicast frame for an inactive VLAN, it will simply drop the frame, reducing the amount of unnecessary network traffic.

VTP Pruning is a configurable feature in Cisco switches and can be enabled or disabled on a per-trunk basis. When enabled, VTP Pruning works dynamically, meaning that VLANs can be marked as active or inactive as needed, based on network traffic patterns.

VTP Pruning is a useful feature for large networks with many VLANs, as it helps to reduce the amount of broadcast and multicast traffic on the network, improving network performance and reducing the risk of network congestion.

VTP Pruning Configuration Commands on Cisco Switches

To configure VTP Pruning on a Cisco switch, you need to follow these steps:

Enable VTP on the switch:

..
switch# vtp mode server
Verify the VTP domain name:

..
switch# show vtp status
Enable VTP Pruning on the switch:

..
switch(config)# vtp pruning
Configure the desired VLANs as active on the trunk:

..
switch(config)# interface [interface_number]
switch(config-if)# switchport trunk allowed vlan [vlan_list]
Verify the VTP Pruning configuration:

..
switch# show interfaces [interface_number] switchport