Cisco WS-C2350-48TD-S Command Reference Manual page 475

Chapter 2 Catalyst 2350 Cisco IOS Commands
To autonegotiate trunking, the interfaces must be in the same VLAN Trunking Protocol (VTP) domain.
Trunk negotiation is managed by the Dynamic Trunking Protocol (DTP), which is a point-to-point
protocol. However, some internetworking devices might forward DTP frames improperly, which could
cause misconfigurations. To avoid this, you should configure interfaces connected to devices that do not
support DTP to not forward DTP frames, which turns off DTP.
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Access ports and trunk ports are mutually exclusive.
Examples This example shows how to configure a port for access mode:
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# switchport mode access
This example shows how set the port to dynamic desirable mode:
Switch(config)# interface gigabitethernet2/0/1
Switch(config-if)# switchport mode dynamic desirable
This example shows how to configure a port for trunk mode:
Switch(config)# interface gigabitethernet2/0/1
Switch(config-if)# switchport mode trunk
You can verify your settings by entering the show interfaces interface-id switchport privileged EXEC
command and examining information in the Administrative Mode and Operational Mode rows.
Related Commands Command
show interfaces
switchport access
switchport trunk
OL-19055-01
If you do not intend to trunk across those links, use the switchport mode access interface
configuration command to disable trunking.
To enable trunking to a device that does not support DTP, use the switchport mode trunk and
switchport nonegotiate interface configuration commands to cause the interface to become a trunk
but to not generate DTP frames.
switchport
Description
Displays the administrative and operational status of a switching
(nonrouting) port, including port blocking and port protection
settings.
Configures a port as a static-access or dynamic-access port.
Configures the trunk characteristics when an interface is in trunking
mode.
Catalyst 2350 Switch Command Reference
switchport mode
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