vtp pruning vs. switchport trunk vlan allowed

smcclenaghansmcclenaghan Senior MemberMember Posts: 139
Does Cisco publish any clear criteria explaining when vtp pruning should be favored over 'switchport trunk vlan allowed' or vice versa?

My best attempts at criteria after a lot of net scouring seem to be:
1) If you have to apply the pruning to specific vlans or specific trunks, choose the 'switchport trunk vlan allowed' method.
2) vtp pruning is an enhancement to a spanning-tree design. So if you're modifying a spanning-tree design, choose vtp pruning.

Without violating NDA from exams, I'd love to hear some of your thoughts on this.


  • kohr-ahkohr-ah Senior Member Member Posts: 1,277
    VTP Pruning = I dont want to tell others about my VLANs
    Switchport trunk vlan allowed = I want this specific device to use these VLANs only

    Perfect Example I have 15 Vlans and I have a wireless controller. The wireless controller utilizes 4 of them. I trunk the wireless controller to my switch and dont want the other 11 vlans to have their information sent over that trunk. I would do switchport trunk vlan allowed and do the 4 vlans the controller needs.
  • smcclenaghansmcclenaghan Senior Member Member Posts: 139
    I appreciate the insight.

    It's a fine line and we're often asked to choose between these two options. I just don't want to screw it up on the exam. Thanks again.
  • linuxabuserlinuxabuser Member Member Posts: 97 ■■□□□□□□□□
    It also matters when you don't run VTP!
  • koz24koz24 Senior Member Member Posts: 766 ■■■■□□□□□□
    When in doubt, switchport trunk allowed vlan is probably the more correct answer. The "Cisco" answer. I had a lot of these types of questions on my exam. Not necessarily vtp pruning vs allowed, but questions where it seemed like there was more than 1 correct answer.
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