Which mode is compatible with Trunk, Access, and desirable ports?

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1. switchport mode access – Always forces that port to be an access port with no VLAN tagging allowed EXCEPT for the voice vlan. DTP is not used and a trunk will never be formed.

   switchport nonegotiate – turns off DTP and forces the interface into a trunk.

   switchport mode dynamic desirable – pro-active DTP negotiation will begin and if the other-side is set to trunk, desirable, or auto. The interface will become a trunk. Otherwise the port will become an access port.

   switchport mode dynamic auto – allows the port to negotiate DTP if the other side is set to trunk or desirable. Otherwise it will become an access port.

   switchport mode trunk – This interface will always be a trunk no matter what happens on the other side. It will also use DTP to negotiate a neighbouring interface that is set to dynamic desirable or dynamic auto into a trunk.

   In the real world – I have never seen *dynamic auto*or dynamic desirable as generally network engineers try and make layer 2 related items (such as switchport settings) stable and static. There are also security risks associated with this.

   An access role port is usually used for an single host or device. You must also specify which VLAN you would like it to be associated with, otherwise it will default to VLAN 1 in the Cisco world. eg)

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