area range (OSPF)

To consolidate and summarize routes at an Open Shortest Path First (OSPF) area boundary, use the area range command. To disable this function, use the no form of this command.

area area-id range ip-prefix [ not-advertise ]

no area area-id range ip-prefix [ not-advertise ]

Syntax Description

area-id
Identifier for the OSPF area where you want to summarize routes. The area ID can be from 0 to 4294967295 or an IP address.
ip-prefix
IP prefix specified as IP address/subnet mask length ( A . B . C . D / LEN ).
not-advertise
(Optional) Sets the address range status to DoNotAdvertise. The Type 3 summary LSA is suppressed, and the component networks remain hidden from other networks.

Command Default

Disabled

Command Modes

Router configuration mode

Command History

Release
Modification
5.0(3)N1(1)
This command was introduced.

Usage Guidelines

Use the area range command only with Area Border Routers (ABRs) to consolidate or summarize routes for an area. The ABR advertises that a single summary route is advertised to other areas and condenses routing information at area boundaries.

You can configure OSPF to summarize addresses for many different sets of address ranges by configuring multiple area range commands.

This command requires the LAN Base Services license.

Examples

This example shows how to configure one summary route to be advertised by the ABR to other areas for all hosts on network 192.0.2.0:

switch(config-if)# interface ethernet 1/2
switch(config-if)# ip address 192.0.2.201 255.255.255.0
switch(config-if)# ip ospf area 201
switch(config-if)# exit
switch(config)# router ospf 12
switch(config-router)# area 0 range 192.0.2.0 255.255.0.0
switch(config-router)#
 

Related Commands

Command
Description
copy running-config startup-config
Saves the configuration changes to the startup configuration file.
show ip ospf
Displays OSPF information.