VTP (v3) pruning of extended VLANs

[Georg Pauwen]

Even though extended VLANs in version 3 are stored in the vlan.dat file (in version 1 and 2 they were not), they still cannor be pruned. What is the reason for that ?

[InayathUlla Sharieff]

Only VLANs included in the pruning-eligible list can be pruned. By default, VLANs 2 through 1001 are pruning-eligible on trunk ports. Reserved VLANs and extended-range VLANs cannotbe pruned.

I believe you have first turned on the VTP prunning on one server(VTP Primary).Then migrate the same to the VTP v3 on client and server.

[Georg Pauwen]

Hello,

thanks for the reply. I wonder if the fact that extended VLANs cannot be pruned is due to a limitation on memory or CPU or trunk capability. I cannot really imagine that to be the reason, since even the high end switches have that limitation.

[asdvads vwe]

S1#sh int f0/1 swi
Name: Fa0/1
Switchport: Enabled
Administrative Mode: trunk
Operational Mode: trunk
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: Off
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Administrative Native VLAN tagging: enabled
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 Native VLAN tagging: enabled
Administrative private-vlan trunk encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk associations: none
Administrative private-vlan trunk mappings: 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
Appliance trust: none

I gues this might be due to the limited VLANs that can be stored in the CAM. 

S1(config-if)#switchport trunk pruning vlan 2000
Command rejected: Bad VLAN list - character #5 (EOL) delimits a VLAN
number (2000) out of the range 1 to 1005. 

And this is what Cisco says: Extended range VLANs are not controlled by VTP. VLANs in the extended range cannot be pruned. The VLAN range for the switchport trunk pruning vlancommand remains 1-1005. The VTP supported VLAN configuration (VLANs 1-1005) is included in the Cisco IOS configuration file only when the device is in VTP transparent mode.