Cisco Catalyst 3550

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Catalyst 3550 Multilayer Switch Command Reference
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Chapter 2 Catalyst 3550 Switch Cisco IOS Commands
switchport mode
switchport mode
Use the switchport mode interface configuration command to configure the VLAN membership mode
of a port. Use the no form of this command to reset the mode to the appropriate default for the device.
switchport mode {access | dot1q-tunnel | dynamic {auto | desirable} | trunk}
no switchport mode {access| dot1q-tunnel | dynamic {auto | desirable} | trunk}
Syntax Description
Defaults The default mode is dynamic desirable.
Command Modes Interface configuration
Command History
Usage Guidelines A configuration that uses the access, trunk, or dot1q-tunnel keywords takes effect only when you
configure the port in the appropriate mode by using the switchport mode command. The static-access
and trunk configuration are saved, but only one configuration is active at a time.
When you enter access mode, the interface changes to permanent nontrunking mode and negotiates to
convert the link into a nontrunk link even if the neighboring interface does not agree to the change.
When you enter trunk mode, the interface changes to permanent trunking mode and negotiates to
convert the link into a trunk link even if the interface connecting to it does not agree to the change.
When you enter dynamic auto mode, the interface converts the link to a trunk link if the neighboring
interface is set to trunk or desirable mode.
access Set the port to access mode (either static-access or dynamic-access depending
on the setting of the switchport access vlan interface configuration command).
The port is set to access unconditionally and operates as a nontrunking, single
VLAN interface that sends and receives nonencapsulated (non-tagged) frames.
An access port can be assigned to only one VLAN.
dot1q-tunnel Set the port as an IEEE 802.1Q tunnel port.
dynamic auto Set the interface trunking mode dynamic parameter to auto to specify that the
interface convert the link to a trunk link.
dynamic desirable Set the interface trunking mode dynamic parameter to desirable to specify that
the interface actively attempt to convert the link to a trunk link.
trunk Set the port to trunk unconditionally. The port is a trunking VLAN Layer 2
interface. The port sends and receives encapsulated (tagged) frames that
identify the VLAN of origination. A trunk is a point-to-point link between two
switches or between a switch and a router.
Release Modification
12.1(4)EA1 This command was introduced.
12.1(9)EA1 The dot1q-tunnel keyword was added.