Specifications

7-15
Cisco MWR 2941 Mobile Wireless Edge Router Release 3.5 Software Configuration Guide, Cisco IOS Release 15.1(3)MR
OL-26895-01
Chapter 7 Configuring VLANs
Configuring VLAN Trunks
If a trunk port with VLAN 1 disabled is converted to a nontrunk port, it is added to the access VLAN.
If the access VLAN is set to 1, the port is added to VLAN 1, regardless of the switchport trunk allowed
setting. The same is true for any VLAN that has been disabled on the port.
A trunk port can become a member of a VLAN if the VLAN is enabled and if the VLAN is in the allowed
list for the port.
Beginning in privileged EXEC mode, follow these steps to modify the allowed list of an
IEEE 802.1Q trunk:
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 on a port:
Router(config)# interface fastethernet0/1
Router(config-if)# switchport trunk allowed vlan remove 2
Router(config-if)# end
Configuring the Native VLAN for Untagged Traffic
A trunk port configured with IEEE 802.1Q tagging can receive both tagged and untagged traffic. By
default, the router forwards untagged traffic in the native VLAN configured for the port. The native
VLAN is VLAN 1 by default.
Note The native VLAN can be assigned any VLAN ID.
For information about IEEE 802.1Q configuration issues, see the “IEEE 802.1Q Configuration
Considerations” section on page 7-12.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
interface interface-id Specify the port to be configured, and enter interface configuration
mode.
Step 3
no shutdown Enable the port, if necessary. By default, UNIs and ENIs are disabled,
and NNIs are enabled.
Step 4
switchport mode trunk Configure the interface as a VLAN trunk port.
Step 5
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,
see 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 6
end Return to privileged EXEC mode.
Step 7
show interfaces interface-id switchport Verify your entries in the Trunking VLANs Enabled field of the display.
Step 8
copy running-config startup-config (Optional) Save your entries in the configuration file.