VLAN C
OMMANDS

3-139

Command Usage
• If switchport mode is set to trunk, then you can only assign an
interface to VLAN groups as a tagged member.
• Frames are always tagged within the switch. The tagged/
untagged parameter used when adding a VLAN to an interface
tells the switch whether to keep or remove the tag from a frame
on egress.
• If none of the intermediate network devices nor the host at the
other end of the connection supports VLANs, the interface
should be added to these VLANs as an untagged member.
Otherwise, it is only necessary to add at most one VLAN as
untagged, and this should correspond to the native VLAN for
the interface.
• If a VLAN on the forbidden list for an interface is manually
added to that interface, the VLAN is automatically removed from
the forbidden list for that interface.
Example
The following example shows how to add VLANs 2, 5 and 6 to the
allowed list as tagged VLANs for port 1:

switchport forbidden vlan

Use this command to configure forbidden VLANs. Use the no form
to remove the list of forbidden VLANs.
Syntax
switchport forbidden vlan {add vlan-list | remove vlan-list}
no switchport forbidden vlan
•add vlan-list - List of VLAN identifiers to add.
•remove vlan-list - List of VLAN identifiers to remove.
Console(config)#interface ethernet 1/1
Console(config-if)#switchport allowed vlan add 2,5,6 tagged
Console(config-if)#
b_mgmt.book Page 139 Tuesday, July 8, 2003 5:24 PM