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 文章录入：csh    责任编辑：csh