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.
When you enter
dynamic desirable
mode, the interface becomes a trunk interface if the neighboring interface
is set to
trunk
,
desirable
, or
auto
mode.
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 problem, configure interfaces connected to devices that do not support DTP to not forward DTP
frames, which turns off DTP.
•
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.
Access ports and trunk ports are mutually exclusive.
The IEEE 802.1x feature interacts with switchport modes in these ways:
•
If you try to enable IEEE 802.1x on a trunk port, an error message appears, and IEEE 802.1x is not
enabled. If you try to change the mode of an IEEE 802.1x-enabled port to trunk, the port mode is not
changed.
•
If you try to enable IEEE 802.1x on a port set to
dynamic auto
or
dynamic desirable
, an error message
appears, and IEEE 802.1x is not enabled. If you try to change the mode of an IEEE 802.1x-enabled port
to
dynamic auto
or
dynamic desirable
, the port mode is not changed.
•
If you try to enable IEEE 802.1x on a dynamic-access (VLAN Query Protocol [VQP]) port, an error
message appears, and IEEE 802.1x is not enabled. If you try to change an IEEE 802.1x-enabled port to
dynamic VLAN assignment, an error message appears, and the VLAN configuration is not changed.
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.
Examples
This example shows how to configure a port for access mode:
Device(config)#
interface gigabitethernet2/0/1
Device(config-if)#
switchport mode access
This example shows how set the port to dynamic desirable mode:
Device(config)#
interface gigabitethernet2/0/1
Device(config-if)#
switchport mode dynamic desirable
This example shows how to configure a port for trunk mode:
Device(config)#
interface gigabitethernet2/0/1
Device(config-if)#
switchport mode trunk
Command Reference, Cisco IOS XE Everest 16.5.1a (Catalyst 3650 Switches)
361
switchport mode
Summary of Contents for Catalyst 3650 Series
Page 2: ... 2017 Cisco Systems Inc All rights reserved ...
Page 37: ...P A R T I Campus Fabric Campus Fabric page 13 ...
Page 38: ......
Page 51: ...P A R T II Interface and Hardware Components Interface and Hardware Commands page 27 ...
Page 52: ......
Page 165: ...P A R T III IP IP page 141 ...
Page 166: ......
Page 235: ...P A R T IV IP Multicast Routing IP Multicast Routing page 211 ...
Page 236: ......
Page 303: ...P A R T V IPv6 IPv6 page 279 ...
Page 304: ......
Page 307: ...P A R T VI Layer 2 3 Layer 2 3 page 283 ...
Page 308: ......
Page 399: ...P A R T VII Multiprotocol Label Switching MPLS MPLS page 375 Multicast VPN page 385 ...
Page 400: ......
Page 429: ...P A R T VIII Network Management Flexible NetFlow page 405 Network Management page 479 ...
Page 430: ......
Page 595: ...P A R T IX Programmability Programmability page 571 ...
Page 596: ......
Page 624: ...Command Reference Cisco IOS XE Everest 16 5 1a Catalyst 3650 Switches 598 ping6 ...
Page 625: ...P A R T X QoS Auto QoS page 601 QoS page 641 ...
Page 626: ......
Page 666: ...Command Reference Cisco IOS XE Everest 16 5 1a Catalyst 3650 Switches 640 show auto qos ...
Page 706: ...Command Reference Cisco IOS XE Everest 16 5 1a Catalyst 3650 Switches 680 trust device ...
Page 707: ...P A R T XI Routing Bidirectional Forwarding Detection page 683 ...
Page 708: ......
Page 725: ...P A R T XII Security Security page 701 ...
Page 726: ......
Page 875: ...P A R T XIII Stack Manager and High Availability Stack Manager and High Availability page 851 ...
Page 876: ......
Page 912: ......
Page 1027: ...P A R T XV VLAN VLAN page 1003 ...
Page 1028: ......
Page 1100: ...Command Reference Cisco IOS XE Everest 16 5 1a Catalyst 3650 Switches 1074 vtp primary ...
Page 1102: ...Command Reference Cisco IOS XE Everest 16 5 1a Catalyst 3650 Switches 1076 Notices ...
Page 1108: ...Command Reference Cisco IOS XE Everest 16 5 1a Catalyst 3650 Switches IN 6 Index ...