Configuring An Ethernet Interface As A Trunk Port; Interaction With Etherchannels; Configuring A Trunk Port - Cisco 3845 - Security Bundle Router Software Manual

Chapter 10 Configuring VLANs

Configuring an Ethernet Interface as a Trunk Port

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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:
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Configuring a Trunk Port

Beginning in privileged EXEC mode, follow these steps to configure a port as an IEEE 802.1Q
trunk port:
Command
Step 1
configure terminal
Step 2
interface interface-id
Step 3 switchport mode trunk
Step 4 switchport access vlan vlan-id
Step 5
switchport trunk native vlan vlan-id
Step 6
end
Step 7
show interfaces interface-id switchport Display the switchport configuration of the interface in the Administrative
Step 8
show interfaces interface-id trunk
Step 9
copy running-config startup-config
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.
OL-23400-01
Interaction with EtherChannels, page 10-11
Defining the Allowed VLANs on a Trunk, page 10-12
Configuring the Native VLAN for Untagged Traffic, page 10-13
Configuring the Native VLAN for Untagged Traffic, page 10-13
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.
Purpose
Enter global configuration mode.
Specify the port to be configured for trunking, and enter interface
configuration mode.
Configure the interface as a Layer 2 trunk.
(Optional) Specify the default VLAN, which is used if the interface stops
trunking.
Specify the native VLAN for IEEE 802.1Q trunks.
Return to privileged EXEC mode.
Mode field of the display.
Display the trunk configuration of the interface.
(Optional) Save your entries in the configuration file.
Cisco ME 3800X and 3600X Switch Software Configuration Guide
Configuring VLAN Trunks
10-11