Setup Guide
• Congure an IP address and mask on the interface.
INTERFACE mode
ip address ip-address mask [secondary]
– ip-address mask: enter an address in dotted-decimal format (A.B.C.D). The mask must be in slash format (/24).
– secondary: the IP address is the interface’s backup IP address. You can congure up to eight secondary IP addresses.
Example of a Conguration for a VLAN Participating in an OSPF Process
interface Vlan 10
ip address 1.1.1.2/24
tagged GigabitEthernet 2/2-2/13
tagged GigabitEthernet 5/1
ip ospf authentication-key force10
ip ospf cost 1
ip ospf dead-interval 60
ip ospf hello-interval 15
no shutdown
!
Loopback Interfaces
A Loopback interface is a virtual interface in which the software emulates an interface. Packets routed to it are processed locally.
Because this interface is not a physical interface, you can congure routing protocols on this interface to provide protocol stability. You can
place Loopback interfaces in default Layer 3 mode.
To congure, view, or delete a Loopback interface, use the following commands.
• Enter a number as the Loopback interface.
CONFIGURATION mode
interface loopback number
The range is from 0 to 16383.
• View Loopback interface congurations.
EXEC mode
show interface loopback number
• Delete a Loopback interface.
CONFIGURATION mode
no interface loopback number
Many of the commands supported on physical interfaces are also supported on a Loopback interface.
Null Interfaces
The Null interface is another virtual interface. There is only one Null interface. It is always up, but no trac is transmitted through this
interface.
To enter INTERFACE mode of the Null interface, use the following command.
• Enter INTERFACE mode of the Null interface.
CONFIGURATION mode
interface null 0
The only congurable command in INTERFACE mode of the Null interface is the ip unreachable command.
Interfaces
365