Reference Guide

Interfaces | 415
Figure 21-4 shows the basic configuration found in a Layer 2 interface.
Figure 21-4. show config Command Example of a Layer 2 Interface
To configure an interface in Layer 2 mode, use these commands in the INTERFACE mode:
For information on enabling and configuring Spanning Tree Protocol, Refer to Spanning Tree Protocol
(STP). To view the interfaces in Layer 2 mode, use the command
show interfaces switchport in the EXEC
mode.
Configuring Layer 3 (Network) Mode
When you assign an IP address to a physical interface, you place it in Layer 3 mode. Use the ip address
command and
no shutdown command in INTERFACE mode to enable Layer 3 mode on an individual
interface. In all interface types except VLANs, the
shutdown command prevents all traffic from passing
through the interface. In VLANs, the
shutdown command prevents Layer 3 traffic from passing through the
interface. Layer 2 traffic is unaffected by the
shutdown command. One of the interfaces in the system must
be in Layer 3 mode before you configure or enter a Layer 3 protocol mode (for example, OSPF).
To view an example of a Layer 3 interface, use the
show config command (Figure 21-5).
Figure 21-5. show config Command Example of a Layer 3 Interface
Command Syntax Command Mode Purpose
no shutdown
INTERFACE Enable the interface.
switchport
INTERFACE Place the interface in Layer 2 (switching) mode.
FTOS(conf-if)#show config
!
interface Port-channel 1
no ip address
switchport
no shutdown
FTOS(conf-if)#
FTOS(conf-if)#show config
!
interface TenGigabitEthernet 1/5
ip address 10.10.10.1 /24
no shutdown
FTOS(conf-if)#