ospf中的新特性，对ios的版本要求较高：



The OSPF ABR Type 3 LSA Filtering feature is supported for the following platforms in Cisco IOS

Release 12.2(4)T:

· Cisco 1400 series

· Cisco 1600 series

· Cisco 1600R series

· Cisco 1720

· Cisco 1721 (Supported in Cisco IOS Release 12.2(8)T and above.)

· Cisco 1750

· Cisco 1751

· Cisco 2500 series

· Cisco 2600 series

· Cisco 3620

· Cisco 3631 (Supported in Cisco IOS Release 12.2(8)T and above.)

· Cisco 3640

· Cisco 3745 (Supported in Cisco IOS Release 12.2(8)T and above.)

· Cisco 3660

· Cisco MC3810

· Cisco 7100 series

· Cisco 7200 series

· Cisco 7500 series (Supported in Cisco IOS Release 12.2(4)T3 and above.)

· Cisco uBR7200 series

· Universal Router Module (Supported in Cisco IOS Release 12.2(8)T.)

以下配置在abr上完成

配置步骤：

1、过滤进入某AREA的LSA3

Command Purpose

Router(config)# router ospf process-id

Configures the router to run an OSPF process.

Router(config-router)# area area-id filter-list prefiXPrefix-list-name in

Configures the router to filter interarea routes into the specified area.

Router(config-router)# ip prefix-list list-name [seq seq-value] deny permit network/len [ge ge-value] [le le-value]

Creates a prefix list with the name specified for thelist-name argument.

2、过滤从某AREA出去的LSA3

Router(config)# router ospf process-id

Configures the router to run an OSPF process.

Router(config-router)# area area-id filter-list prefix prefix-list-name out

Configures the router to filter interarea routes out of the specified area.

Router(config-router)# ip prefix-list list-name [seq seq-value] deny permit network/len [ge ge-value] [lele-value]

Creates a prefix list with the name specified for the list-name argument.

3、检查配置

router# show ip ospf 1

Routing Process "ospf 1" with ID 172.16.0.1

Supports only single TOS(TOS0) routes

Supports opaque LSA

It is an area border router

SPF schedule delay 5 secs, Hold time between two SPFs 10 secs

Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs

Number of external LSA 0. Checksum Sum 0x0

Number of opaque AS LSA 0. Checksum Sum 0x0

Number of DCbitless external and opaque AS LSA 0

Number of DoNotAge external and opaque AS LSA 0

Number of areas in this router is 2. 2 normal 0 stub 0 nssa

External flood list length 0

Area BACKBONE(0)

Number of interfaces in this area is 2

Area has no authentication

SPF algorithm executed 6 times

Area ranges are

10.0.0.0/8 Passive Advertise

Area-filter AREA_0_IN in

Area-filter AREA_0_OUT out

Number of LSA 5. Checksum Sum 0x29450

4、配置举例

Router(config)# router ospf 1

log-adjacency-changes

area 1 filter-list prefix AREA_1_OUT out

area 3 filter-list prefix AREA_3_IN in

network 10.0.0.0 0.255.255.255 area 3

network 172.16.1.0 0.0.0.255 area 0

network 192.168.0.0 0.255.255.255 area 1

!

ip prefix-list AREA_1_OUT seq 10 permit 10.25.0.0/8 ge 16

ip prefix-list AREA_1_OUT seq 20 permit 172.20.20.0/24

!

ip prefix-list AREA_3_IN seq 10 permit 172.31.0.0/16