How to Configure VTP Pruning on Cisco Switch

VTP pruning increases the network bandwidth by reducing unnecessary flooded traffic, such as broadcast, multicast, unknown, and flooded unicast packets on trunk links. Without VTP pruning, a switch floods broadcast, multicast, and unknown unicast traffic across all trunk links within a VTP domain even though receiving switches might discard them. By default, VTP pruning is disabled. VTP pruning does not prune traffic from VLANs that are pruning-ineligible.

VTP pruning blocks unneeded flooded traffic to VLANs on trunk ports that are included in the pruning-eligible list. Only VLANs included in the pruning-eligible list can be pruned. By default, VLANs 2 through 1001 are pruning eligible switch trunk ports. VTP pruning does not prune traffic from VLANs that are pruning-ineligible. VLAN 1 and VLANs 1002 to 1005 are always pruning-ineligible; traffic from these VLANs cannot be pruned. Extended-range VLANs (VLAN IDs higher than 1005) are also pruning-ineligible. VTP pruning is supported with VTP version 1 and version 2.

Key Points on VTP Pruning

  • VLAN 1(default or Native), VLANs 1002 to 1005 is always pruning-ineligible, meaning traffic from VLAN 1, VLANs 1002 to 1005 cannot be pruned in any situation. Extended-range VLANs (VLAN IDs higher than 1005) are also pruning-ineligible.
  • Pruning eligibility is based only on the VLANs that need the given broadcast information across the trunks. It is not related with the number of ports assigned to that VLAN.
  • VTP Pruning does not change, add, or delete the VLANs in a VTP domain, it simply reduces the broadcast and multicast traffic.
  • VTP version 2 and VTP version 1 are not interoperable on network devices in the same VTP domain. Every network device in the VTP domain must use the same VTP version. Do not enable VTP version 2 unless every network device in the VTP domain supports version 2.

VTP Pruning Step By Step Configuration

1. Enabling VTP pruning on a VTP server enables pruning for the entire management domain. Making VLANs pruning-eligible or pruning-ineligible affects pruning eligibility for those VLANs on that device only (not on all switches in the VTP domain). Find the below VTP Pruning configuration on Cisco Switch.

For Enable VTP Pruning:

Cisco-Switch(config)#vtp pruning enable

For Disable VTP Pruning:

Cisco-Switch(config)#vtp pruning disable

VTP pruning is not designed to function in VTP transparent mode. If one or more switches in the network are in VTP transparent mode, you should do one of these:

• Turn off VTP pruning in the entire network.

• Turn off VTP pruning by making all VLANs on the trunk of the switch upstream to the VTP transparent switch pruning ineligible

2. For VTP Pruning eligible list configuration, we should add or remove VLANs on trunk interfaces by using switchport trunk pruning vlan interface configuration command. VTP pruning operates when an interface is trunking.

Cisco-Switch#config term

Cisco-Switch(config)#interface interface-id

Cisco-Switch(config)#switchport trunk pruning vlan {add | except | none | remove}  vlan-list [,vlan[,vlan[,,,]]

Cisco-Switch(config)#end

Cisco-Switch(config)#wr

Verify VTP Pruning status

By default VTP pruning disabled after after vtp configuration, you can view the configuration with the following command:
Cisco-Switch#show vtp
VTP Version : 2
Configuration Revision : 2
Maximum VLANs supported locally : 1005
Number of existing VLANs : 2
VTP Operating Mode : Server
VTP Password : ccna
VTP Domain Name : cisco
VTP Pruning Mode : Disabled
VTP V2 Mode : Disabled
VTP Traps Generation : Enabled
MD5 digest : 0xB9 0xC7 0x8D 0xB3 0xD4 0xBA 0×94 0×03
Configuration last modified by 192.168.1.86 at 7-25-01 01:22:24

After VTP Pruning enabled, you can view the configuration with the following command:

Cisco-Switch#show vtp
VTP Version : 2
Configuration Revision : 2
Maximum VLANs supported locally : 1005
Number of existing VLANs : 2
VTP Operating Mode : Server
VTP Password : ccna
VTP Domain Name : cisco
VTP Pruning Mode : Enabled
VTP V2 Mode : Disabled
VTP Traps Generation : Enabled
MD5 digest : 0xB9 0xC7 0x8D 0xB3 0xD4 0xBA 0×94 0×03
Configuration last modified by 192.168.1.86 at 7-25-01 01:22:24

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  1. Uday says:

    Good one on VTP pruning configuration on Cisco Switch to avoid unnecessary traffic. Thanks

  2. Durga says:

    You have covered key points on VTP pruning on Cisco Switch and configuration steps. Thanks for sharing.

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