Configuring The Native Vlan For Untagged Traffic - Cisco Catalyst 3550 series Software Configuration Manual

Chapter 12 Configuring VLANs
Command
Step 5 show interfaces interface-id switchport Verify your entries in the Pruning VLANs Enabled field of the display.
Step 6
copy running-config startup-config
To return to the default pruning-eligible list of all VLANs, use the no switchport trunk pruning vlan
interface configuration command.

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 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 802.1Q configuration issues, see the
section on page
Beginning in privileged EXEC mode, follow these steps to configure the native VLAN on an 802.1Q
trunk:
Command
Step 1
configure terminal
Step 2
interface interface-id
Step 3
switchport trunk native vlan vlan-id
Step 4 end
Step 5
show interfaces interface-id switchport
Step 6
copy running-config startup-config
To return to the default native VLAN, VLAN 1, use the no switchport trunk native vlan interface
configuration command.
If a packet has a VLAN ID that is the same as the outgoing port native VLAN ID, the packet is sent
untagged; otherwise, the switch sends the packet with a tag.
Load Sharing Using STP
Load sharing divides the bandwidth supplied by parallel trunks connecting switches. To avoid loops,
STP normally blocks all but one parallel link between switches. Using load sharing, you divide the
traffic between the links according to which VLAN the traffic belongs.
78-11194-09
Purpose
(Optional) Save your entries in the configuration file.
12-18.
Purpose
Enter global configuration mode.
Enter interface configuration mode, and define the interface that is
configured as the 802.1Q trunk.
Configure the VLAN that is sending and receiving untagged traffic
on the trunk port.
For vlan-id, the range is 1 to 4094.
Return to privileged EXEC mode.
Verify your entries in the Trunking Native Mode VLAN field.
(Optional) Save your entries in the configuration file.
Catalyst 3550 Multilayer Switch Software Configuration Guide
Configuring VLAN Trunks
"802.1Q Configuration Considerations"
12-23