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Cisco ME 3800X and 3600X Switch Software Configuration Guide
OL-23400-01
Chapter 10 Configuring VLANs
Configuring VLAN Trunks
Configuring an Ethernet Interface as a Trunk Port
•
Interaction with EtherChannels, page 10-11
•
Defining the Allowed VLANs on a Trunk, page 10-12
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Configuring the Native VLAN for Untagged Traffic, page 10-13
•
Configuring the Native VLAN for Untagged Traffic, page 10-13
Interaction with EtherChannels
Trunk ports can be grouped into EtherChannel port groups, but all trunks in the group must have the same
configuration. When a group is first created, all ports follow the parameters set for the first port to be
added to the group. If you change the configuration of one of these parameters, the switch propagates
the setting that you entered to all ports in the group:
•
allowed-VLAN list.
•
STP port priority for each VLAN.
•
STP Port Fast setting.
•
trunk status: if one port in a port group ceases to be a trunk, all ports cease to be trunks.
Configuring a Trunk Port
Beginning in privileged EXEC mode, follow these steps to configure a port as an IEEE 802.1Q
trunk port:
To return an interface to its default configuration, use the default interface interface-id interface
configuration command. To reset all trunking characteristics of a trunking interface to the defaults, use
the no switchport trunk interface configuration command. To disable trunking, use the switchport
mode access interface configuration command to configure the port as a static-access port.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Specify the port to be configured for trunking, and enter interface
configuration mode.
Step 3
switchport mode trunk
Configure the interface as a Layer 2 trunk.
Step 4
switchport access vlan vlan-id
(Optional) Specify the default VLAN, which is used if the interface stops
trunking.
Step 5
switchport trunk native vlan vlan-id
Specify the native VLAN for IEEE 802.1Q trunks.
Step 6
end
Return to privileged EXEC mode.
Step 7
show interfaces interface-id switchport Display the switchport configuration of the interface in the Administrative
Mode field of the display.
Step 8
show interfaces interface-id trunk
Display the trunk configuration of the interface.
Step 9
copy running-config startup-config
(Optional) Save your entries in the configuration file.