Cisco Catalyst 4500 Series Command Reference Manual page 1076

switchport trunk
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Follow these guidelines for native VLAN tagging:
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Examples This example shows how to cause a port interface that is configured as a switched interface to
encapsulate in 802.1Q trunking format regardless of its default trunking format in trunking mode:
Switch(config-if)# switchport trunk encapsulation dot1q
Switch(config-if)#
This example shows how to enable 802.1Q tagging on a port:
Switch(config-if)# switchport trunk native vlan tag
Switch(config-if)#
This example shows how to configure a secure MAC-address and a maximum limit of secure MAC
addresses on Gigabit Ethernet port 1 for all VLANs:
Switch(config)# interface gigabitethernet1/1
Switch(config-if)# switchport trunk encapsulation dot1q
Switch(config-if)# switchport mode trunk
Switch(config-if)# switchport port-security
Switch(config-if)# switchport port-security maximum 3
This example shows how to configure a secure MAC-address on Gigabit Ethernet port 1 in a specific
VLAN or range of VLANs:
Switch(config)# interface gigabitethernet1/1
Switch(config-if)# switchport trunk encapsulation dot1q
Switch(config-if)# switchport mode trunk
Switch(config-if)# switchport port-security
Switch(config-if)# vlan-range 2-6
Switch(config-if-vlan-range)# port-security maximum 3
This example shows how to configure a secure MAC-address in a VLAN on Gigabit Ethernet port 1:
Switch(config)# interface gigabitethernet1/1
Switch(config-if)# switchport trunk encapsulation dot1q
Switch(config-if)# switchport mode trunk
Switch(config-if)# switchport port-security
Switch(config-if)# switchport port-security mac-address sticky
Switch(config-if)# vlan-range 2-6
Switch(config-if-vlan-range)# port-security mac-address 1.1.1
Switch(config-if-vlan-range)# port-security mac-address sticky 1.1.2
Switch(config-if-vlan-range)# port-security mac-address sticky 1.1.3
Catalyst 4500 Series Switch Cisco IOS Command Reference—Release IOS XE 3.3.0SG and IOS 15.1(1)SG)
2-1018
If you are connecting multiple Cisco switches to a non-Cisco 802.1Q network, all of the connections
must be through the 802.1Q trunks. You cannot connect Cisco switches to a non-Cisco 802.1Q
network through the ISL trunks or through the access ports. This action causes the switch to place
the ISL trunk port or access port into the spanning-tree "port inconsistent" state and no traffic will
pass through the port.
The no switchport trunk native vlan tag command disables the native VLAN tagging operation on
a port. This overrides the global tagging configuration.
The switchport trunk native vlan tag command can be used to reenable tagging on a disabled port.
The no option is saved to NVRAM so that the user does not have to manually select the ports to
disable the tagging operation each time that the switch reboots.
When the switchport trunk native vlan tag command is enabled and active, all packets on the
native VLAN are tagged, and incoming untagged data packets are dropped. Untagged control
packets are accepted.
Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
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