Create Trunk for VLAN 20

ADE

To create a trunk that allows VLAN 20, the following three commands must be entered:

A. Switch(config-if)#switchport mode trunk: This command puts the interface into trunking mode, enabling it to carry multiple VLANs.

D. Switch(config-if)#switchport trunk encapsulation dot1q: This command sets the trunking encapsulation protocol to IEEE 802.1Q, which is the most commonly used trunking protocol.

E. Switch(config-if)#switchport trunk allowed vlan 20: This command specifies that VLAN 20 is allowed on the trunk, allowing traffic for that VLAN to pass through the interface.

The other options are:

B. Switch(config-if)#switchport mode dynamic desirable: This command sets the interface to actively negotiate the trunking mode with the other end of the link. However, it may result in a non-trunk link if the other end is not configured for trunking.

C. Switch(config-if)#switchport trunk native vlan 20: This command specifies that VLAN 20 is the native VLAN on the trunk. The native VLAN is the VLAN that is used for untagged traffic on a trunk. However, it is not necessary to configure a native VLAN for a trunk to work.

F. Switch(config-if)#switchport mode dynamic auto: This command sets the interface to passively wait for the other end of the link to initiate trunk negotiation. However, it may result in a non-trunk link if the other end is not configured for trunking.

So, options A, D, and E are the correct commands to create a trunk that allows VLAN 20.