8-43
Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
78-6511-05
Chapter 8 Configuring VLANs
How VLAN Trunks Work
Configuring the Native VLAN for Untagged Traffic
A trunk port configured with 802.1Q tagging can receive both tagged and
untagged traffic. By default, the switch forwards untagged traffic with 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, and it is not dependent on
the management VLAN.
For information about 802.1Q configuration issues, see the
“IEEE 802.1Q
Configuration Considerations” section on page 8-37
.
Beginning in privileged EXEC mode, follow these steps to configure the native
VLAN on an 802.1Q trunk:
If a packet has a VLAN ID the same as the outgoing port native VLAN ID, the
packet is transmitted untagged; otherwise, the switch transmits the packet with
a tag.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Enter interface configuration mode, and define the
interface that is configured as the 802.1Q trunk.
Step 3
switchport trunk native vlan
vlan-id
Configure the VLAN that is sending and receiving
untagged traffic on the trunk port.
Valid IDs are from 1 to 1001.
Step 4
show interface interface-id
switchport
Verify your settings.