Reference Guide

• Configuring Layer 2 (Interface) Mode
• Management Interfaces
• Auto-Negotiation on Ethernet Interfaces
• Adjusting the Keepalive Timer
• Clearing Interface Counters
Overview of Layer Modes
On all systems running FTOS, you can place physical interfaces, port channels, and VLANs in Layer 2 mode or Layer 3
mode.
By default, VLANs are in Layer 2 mode.
Type of Interface Possible Modes Requires Creation Default State
10/100/1000 Ethernet,
Gigabit Ethernet, 10 Gigabit
Ethernet
Layer 2
Layer 3
No Shutdown (disabled)
SONET (PPP encapsulation) Layer 3 No Shutdown (disabled)
Management N/A No Shutdown (disabled)
Loopback Layer 3 Yes No shutdown (enabled)
Null interface N/A No Enabled
Port Channel
Layer 2
Layer 3
Yes Shutdown (disabled)
VLAN
Layer 2
Layer 3
Yes, except for the default
VLAN.
No shutdown (active for
Layer 2)
Shutdown (disabled for
Layer 3)
Configuring Layer 2 (Data Link) Mode
Do not configure switching or Layer 2 protocols such as spanning tree protocol (STP) on an interface unless the
interface has been set to Layer 2 mode.
To set Layer 2 data transmissions through an individual interface, use the following command.
• Enable Layer 2 data transmissions through an individual interface.
INTERFACE mode
switchport
Example of a Basic Layer 2 Interface Configuration
FTOS(conf-if)#show config
!
interface Port-channel 1
no ip address
switchport
no shutdown
FTOS(conf-if)#
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