Administrator Guide

Configuring Layer 3 (Network) Mode
When you assign an IP address to a physical interface, you place it in Layer 3 mode.
To enable Layer 3 mode on an individual interface, use the following commands. 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).
• Enable Layer 3 on an individual interface
INTERFACE mode
ip address ip-address
• Enable the interface.
INTERFACE mode
no shutdown
Example of Error Due to Issuing a Layer 3 Command on a Layer 2 Interface
If an interface is in the incorrect layer mode for a given command, an error message is displayed (shown in bold). In the following example,
the
ip address command triggered an error message because the interface is in Layer 2 mode and the ip address command is a
Layer 3 command only.
Dell(conf-if)#show config
!
interface TenGigabitEthernet 1/2
no ip address
switchport
no shutdown
Dell(conf-if)#ip address 10.10.1.1 /24
% Error: Port is in Layer 2 mode Te 1/2.
Dell(conf-if)#
To determine the configuration of an interface, use the show config command in INTERFACE mode or the various show interface
commands in EXEC mode.
Configuring Layer 3 (Interface) Mode
To assign an IP address, use the following commands.
• Enable the interface.
INTERFACE mode
no shutdown
• Configure a primary IP address and mask on the interface.
INTERFACE mode
ip address ip-address mask [secondary]
The ip-address must be in dotted-decimal format (A.B.C.D) and the mask must be in slash format (/xx).
Add the keyword secondary if the IP address is the interface’s backup IP address.
Example of the show ip interface Command
You can only configure one primary IP address per interface. You can configure up to 255 secondary IP addresses on a single interface.
Interfaces
395