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12-22
Catalyst 3550 Multilayer Switch Software Configuration Guide
78-11194-09
Chapter 12 Configuring VLANs
Configuring VLAN Trunks
To return to the default allowed VLAN list of all VLANs, use the no switchport trunk allowed vlan
interface configuration command.
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 must be enabled for this procedure to take effect. The
“Enabling VTP Pruning” section on
describes how to enable VTP pruning.
Beginning in privileged EXEC mode, follow these steps to remove VLANs from the pruning-eligible list
on a trunk port:
Step 4
switchport trunk allowed vlan {add |
all | except | remove} vlan-list
(Optional) Configure the list of VLANs allowed on the trunk.
For explanations about using the add, all, except, and remove keywords,
refer to the command reference for this release.
The vlan-list parameter is either a single VLAN number from 1 to 4094
or a range of VLANs described by two VLAN numbers, the lower one
first, separated by a hyphen. Do not enter any spaces between
comma-separated VLAN parameters or in hyphen-specified ranges.
All VLANs are allowed by default.
Step 5
end
Return to privileged EXEC mode.
Step 6
show interfaces interface-id switchport Verify your entries in the Trunking VLANs Enabled field of the display.
Step 7
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Command
Purpose
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Enter interface configuration mode, and select the trunk port for which
VLANs should be pruned.
Step 3
switchport trunk pruning vlan {add |
except | none | remove} vlan-list
[,vlan[,vlan[,,,]]
Configure the list of VLANs allowed to be pruned from the trunk. (See
the
“VTP Pruning” section on page 13-4
For explanations about using the add, except, none, and remove
keywords, refer to the command reference for this release.
Separate nonconsecutive VLAN IDs with a comma and no spaces; use a
hyphen to designate a range of IDs. Valid IDs are from 2 to 1001.
Extended-range VLANs (VLAN IDs 1006 to 4094) cannot be pruned.
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.