Cisco Catalyst 2950 Command Reference Manual page 539

Chapter 2 Catalyst 2950 and 2955 Cisco IOS Commands
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Trunk Pruning:
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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
show interfaces
switchport mode
0L-10102-01
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.
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.
switchport
Description
Displays the administrative and operational status of a switching
(nonrouting) port.
Configures the VLAN membership mode of a port.
Catalyst 2950 and Catalyst 2955 Switch Command Reference
switchport trunk
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