switchport trunk




switchport trunk encapsulation {isl | dot1q}

no switchport trunk encapsulation

Syntax Description:


Set the encapsulation format to Inter-Switch Link (ISL). The switch encapsulates all received and transmitted packets with an ISL header. The switch filters native frames received from an ISL trunk port.


Set the tagging format to IEEE 802.1Q. With this format, the switch supports simultaneous tagged and untagged traffic on a port.

Command Description:

Use the switchport trunk encapsulation interface configuration command to set the encapsulation format on the trunk port. Use the no form of this command to reset the format to the default. This command is available only in the Enterprise Edition Software.

You cannot configure one end of the trunk as an 802.1Q trunk and the other end as an ISL or nontrunk port. However, you can configure one port as an ISL trunk and another port on the same switch as a 802.1Q trunk.

This command is only applicable on switch platforms and port hardware that support both formats.


The following example shows how to configure the encapsulation format to 802.1Q:

Switch(config-if)#switchport trunk encapsulation dot1q

You can verify the previous command by entering the show interface interface-id switchport command in privileged EXEC mode.


Related commands:



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