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Catalyst 2950 Desktop Switch Software Configuration Guide
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Chapter 14 Co n figuring VLANs
Configur ing VLAN Trunks
This example shows how to remove VLAN 2 from the allowed VLAN list:
Switch(config)# interface fastethernet0/1
Switch(config-if)# switchport trunk allowed vlan remove 2
Switch(config-if)# end
Switch#

Changing the Pruning-Eligible List

The pruning-eligible list applies only to trunk ports. Each trunk port has its own eligibility list. VTP
pruning m ust b e en ab led for t h is pr oc ed ure t o ta ke effect. The “Ena bling VTP Pruning” section on
page 15-14 describ es how to ena ble V TP pr uning .
Beginning in privileged EXEC mode, follow these steps to remove VLANs from the pruning-eligible
list on a trunk por t:
To return to the default pruning-eligible list of all VLANs, use the no switchport trunk pruning vlan
interface configuration command.

Configuring the Native VLAN for Untagged Traffic

A trunk port configured with 802 .1Q tagg ing can re ceive both tagged and unt agged tra ffic. By default,
the switch forwards untagged traffic in the native VLAN configured for the port. The native VLAN is
VLAN 1 by default.
Note Th e native VLAN can be assign ed any VLAN ID; it is not depe nden t on the manag ement VLAN.
For informat ion about 802.1Q co nfigurati on issues, se e the “802.1Q Configuratio n Consider ation s”
section on page 14-1 6.
Command Purpose
Step 1 configure terminal Enter glob al con figuration mo de.
Step 2 interface interface-id Enter interfac e configurat ion mode , and sel ect the t runk por t for which
VLANs sho uld be pr uned.
Step 3 switchport trunk pruning vlan {add |
except | none | remove} vlan-list
[,vlan[,vlan[,,,]]
Configure the list of VL ANs allowed to be prune d from the trunk. (See
the “VT P Pr uning” se ction on page 15-4).
For explanations ab out using the add, except, none, and remove
keywords, refe r to the co mman d referen ce for this rel ease.
Separate nonconsecutive VLAN IDs with a comma and no spaces; use a
hyphen to desig nate a range of IDs. Valid IDs are fro m 2 to 1001.
Extend ed-ra ng e VL AN s ( VLA N ID s 100 6 to 40 94) c anno t be p run ed.
VLANs that are pruning-ineligible receive flooded traffic.
The default list of VLANs allowed to be pruned contains VLANs 2 to
1001.
Step 4 end Return to privileged EXEC mode.
Step 5 show interfaces interface-id switchport Verify your entries in the Pruni ng V LAN s E nab led field of the display.
Step 6 copy running-config startup-config (Optional) Save your entries in the configuration file.