配置实例:如何过滤ospf中的lsa3

　　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