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Catalyst 2950 and Catalyst 2955 Switch Command Reference
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Chapter 2 Catalyst 2950 and 2955 Cisco IOS Commands
switchport trunk
• If a packet has a VLAN ID that is the same as the sending port native VLAN ID, the packet is sent
without a tag; otherwise, the switch sends the packet with a tag.
• The no form of the native vlan command resets the native mode VLAN to the appropriate default
VLAN for the device.
Trunk Pruning:
• The pruning-eligible list applies only to trunk ports.
• Each trunk port has its own eligibility list.
• If you do not want a VLAN to be pruned, remove it from the pruning-eligible list. VLANs that are
pruning-ineligible receive flooded traffic.
• VLAN 1, VLANs 1002 to 1005, and extended-range VLANs (VLANs 1006 to 4094) cannot be
pruned.
Note The switch does not support Inter-Switch Link (ISL) trunking.
Examples This example shows how to configure VLAN 3 as the default port to send all untagged traffic:
Switch(config-if)# switchport trunk native vlan 3
This example shows how to add VLANs 1, 2, 5, and 6 to the allowed list:
Switch(config-if)# switchport trunk allowed vlan add 1,2,5,6
This example shows how to remove VLANs 3 and 10 to 15 from the pruning-eligible list:
Switch(config-if)# switchport trunk pruning vlan remove 3,10-15
You can verify your settings by entering the show interfaces interface-id switchport privileged EXEC
command.
Related Commands Command Description
show interfaces switchport Displays the administrative and operational status of a switching
(nonrouting) port.
switchport mode Configures the VLAN membership mode of a port.