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area range
Creates/deletes an area address range entry and optionally specifies whether to advertise the addresses.
Syntax: [no] area area-id range address mask [do-not-advertise]
area-id
The identifier for the area. This number can be in either decimal or dotted decimal Internet address format.
address
An IP address in dotted decimal notation. This address is an aggregate address or subnet address which, when combined with the mask, defines the addresses that make up the area.
mask
A class A, B, or C network mask used to further define the address as an area.
do-not-advertise
Do not advertise (hide) these networks from other areas.
Description: Address ranges are used to aggregate address ranges from within the area into one single advertisement sent into the adjacent areas, or to prevent the advertisement of networks.
An OSPF area is defined as a list of address ranges. Each address range consists of an address and mask pair. Area range entries are used to aggregate network information before the advertisements are flooded into the backbone. A single summary LSA is originated for each range.
Overlapping area ranges are supported. By default, a Type 3 summary LSA is generated with Link State ID equal to the range's address. If necessary, the Link State ID can also have one or more of the range's host bits set and cost equal to the largest cost of any of the component networks. When the range's status indicates DoNotAdvertise, the Type 3 summary LSA is suppressed and the component networks remain hidden from other areas.
Use the area area-id range address mask command create an address range.
Use the area area-id range address mask do-not-advertise command to create an address range and prevent the range from being advertised to other networks.
Use the no area area-id range address mask command delete an address range.
Factory Default: No area ranges configured.
Command Mode: Router configuration.
Example: In the following example,
- The router ospf command enables OSPF and specifies an OSPF process number
- The two network area commands enable OSPF on two networks and assigns them an area ID of 1
- The area range command encloses the two networks (192.12.1.0 and 192.12.3.0) into an address range entry 192.12.0.0. The router will generate a single summary advertisement into the backbone for 192.12.0.0.
router(config)#router ospf 12
router(config-router)#network 192.12.1.0 0.0.0.255 area 1
router(config-router)#network 192.12.3.0 0.0.0.255 area 1
router(config-router)#area 1 range 12.1.0.0 255.255.0.0
Related Commands: area default-cost
ip ospf authentication-key
network area
area stub
router ospf
interface
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Copyright © 2004
Avici Systems Inc.
Avici® and TSR®
is a registered trademark of Avici Systems Inc.
IPriori™, Composite Links™, SSR™, QSR, and NSR® are
trademarks of Avici Systems Inc.
Source
File Name: ospf.fm
HTML File Name: ospf4.html
Last Updated: 05/10/04 at 16:34:58