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Pruning

vu2jjq
Beginner
Beginner

Hello,

I am using vlan 13 as my native vlan with dot1q trunking. I have enabled VTP pruning.

When I see the show interface trunk command, even the native vlan 13 is pruned. Is there any implication on the functionality in such case? How can I make a vlan non-prunable?

TIA

8 REPLIES 8

hi,

so no vlan traffic is passing the link?

kamal-learn
Enthusiast
Enthusiast

hi

VTP pruning does not prune traffic from VLANs that are pruning-ineligible such as native vlan always 1 unless you change it.

i think you enabled pruning before changing the native vlan, undo your work and change the native first and enable pruning second.

and let us know

HTH

Native vlan is set on vlan 13, before enable pruning. But all I see is the following:-

-----

Port Mode Encapsulation Status Native vlan

Gi3/8 on 802.1q trunking 13

Port Vlans allowed on trunk

Gi3/8 1-4094

Port Vlans allowed and active in management domain

Gi3/8 1,13,15,20-21,25,30,35,40,45,50,55,60,65,70,75,80,85,90,100,105,500

Port Vlans in spanning tree forwarding state and not pruned

Gi3/8 1,30,40

-----

The following is the interface config:

--

switchport

switchport trunk encapsulation dot1q

switchport trunk native vlan 13

switchport mode trunk

---

Again my question is how to forward vlan 13 and not to be pruned.

Thanks

hi,

Is spanning tree blocking this link?

Are you using per vlan spanntree?

regards

J.

Hello,

PVST is being used.

There is only a single uplink to this switch to the downstream one. It is not in blocked state.

Regards

JJQ

Can you post the sh trunk on both sides. Or sh int gig X/x trunk, sh int gig x/x switchport

thanks

J

Hi,

Please explain your network connectivity. I believe that you have not manually taken the vlan 13 from the trunk interface of the other switch.

Do you have any PC connected in vlan 13 on this switch?If you dont have any PC in this switch this vlan will be pruned on the trunk interface. This is how VTP pruning work. If you have even a single host in the vlan 13on this switch the vlan will be in STP forwarding and non-pruned state.

HTH,

-amit singh

From the Dist Switch:-

--

LAW-SOCSCI#sh int gi 3/8 switchport

Name: Gi3/8

Switchport: Enabled

Administrative Mode: trunk

Operational Mode: trunk

Administrative Trunking Encapsulation: dot1q

Operational Trunking Encapsulation: dot1q

Negotiation of Trunking: On

Access Mode VLAN: 1 (default)

Trunking Native Mode VLAN: 13 (Native_VLAN_for_dot1q)

Voice VLAN: none

Administrative private-vlan host-association: none

Administrative private-vlan mapping: none

Administrative private-vlan trunk native VLAN: none

Administrative private-vlan trunk encapsulation: dot1q

Administrative private-vlan trunk normal VLANs: none

Administrative private-vlan trunk private VLANs: none

Operational private-vlan: none

Trunking VLANs Enabled: ALL

Pruning VLANs Enabled: 2-1001

Capture Mode Disabled

Capture VLANs Allowed: ALL

Voice VLAN: none (Inactive)

Appliance trust: none

----

From the Edge Switch

---

SS-G-FF-3550-24PWR-6#sh int gi 0/1 switchport

Name: Gi0/1

Switchport: Enabled

Administrative Mode: trunk

Operational Mode: trunk

Administrative Trunking Encapsulation: dot1q

Operational Trunking Encapsulation: dot1q

Negotiation of Trunking: On

Access Mode VLAN: 1 (default)

Trunking Native Mode VLAN: 13 (Native_VLAN_for_dot1q)

Voice VLAN: none

Administrative private-vlan host-association: none

Administrative private-vlan mapping: none

Operational private-vlan: none

Trunking VLANs Enabled: ALL

Pruning VLANs Enabled: 2-1001

Capture Mode Disabled

Capture VLANs Allowed: ALL

Protected: false

Unknown unicast blocked: disabled

Unknown multicast blocked: disabled

Voice VLAN: none (Inactive)

Appliance trust: none

SS-G-FF-3550-24PWR-6#

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