Cisco Systems 3560 사용자 설명서

 lists the Ethernet trunk encapsulation types and keywords.

The switch does not support Layer 3 trunks; you cannot configure subinterfaces or use the 
encapsulation keyword on Layer 3 interfaces. The switch does support Layer 2 trunks and Layer 3 
VLAN interfaces, which provide equivalent capabilities.

The trunking mode, the trunk encapsulation type, and the hardware capabilities of the two connected 
interfaces decide whether a link becomes an ISL or IEEE 802.1Q trunk.

Puts the interface (access port) into permanent nontrunking mode and negotiates to 
convert the link into a nontrunk link. The interface becomes a nontrunk interface 
regardless of whether or not the neighboring interface is a trunk interface.

Makes the interface able to convert the link to a trunk link. The interface becomes a trunk 
interface if the neighboring interface is set to trunk or desirable mode. The default 
switchport mode for all Ethernet interfaces is dynamic auto.

Makes the interface actively attempt to convert the link to a trunk link. The interface 
becomes a trunk interface if the neighboring interface is set to trunk, desirable, or auto 
mode. 

Puts the interface into permanent trunking mode and negotiates to convert the 
neighboring link into a trunk link. The interface becomes a trunk interface even if the 
neighboring interface is not a trunk interface.

Prevents the interface from generating DTP frames. You can use this command only 
when the interface switchport mode is access or trunk. You must manually configure the 
neighboring interface as a trunk interface to establish a trunk link.

Configures the interface as a tunnel (nontrunking) port to be connected in an asymmetric 
link with an IEEE 802.1Q trunk port. The IEEE 802.1Q tunneling is used to maintain 
customer VLAN integrity across a service provider network. See 

 for more information on 

tunnel ports.

Specifies ISL encapsulation on the trunk link.

Specifies IEEE 802.1Q encapsulation on the trunk link.

switchport trunk encapsulation negotiate  Specifies that the interface negotiate with the neighboring interface to become 

an ISL (preferred) or IEEE 802.1Q trunk, depending on the configuration and 
capabilities of the neighboring interface. This is the default for the switch.