OSPF ABR Type 3 LSA Filtering
Document ID: 00007
目录
提要
正文
TOPO 如下
基本配置如下
验证
附注
提要：
讨论 OSPF ABR Type 3 LSA Filtering
cisco文档关于OSPF ABR Type 3 LSA Filtering的解释
正文 ：
OSPF ABR Type 3 LSA Filtering 只能在 ABR 上面做
TOPO 如下 ：    
基本配置如下 ：
l        R1
l        R2
l        R3
R1
interface Loopback0
 ip address 1.1.1 .1 255.255.255.0
 ip ospf network point-to-point
!
interface Serial1/0
 ip address 12.1.1 .1 255.255.255.0
 serial restart-delay 0
 no fair-queue
!
interface Serial2/0
 ip address 13.1.1 .1 255.255.255.0
 serial restart-delay 0
!
router ospf 1
 router-id 1.1.1 .1
 log-adjacency-changes
 network 12.1.1 .0 0.0.0.255 area 0
 network 13.1.1 .0 0.0.0.255 area
 
 
R2
interface Loopback0
 ip address 2.2.2 .2 255.255.255.0
!
interface Serial2/0
 ip address 12.1.1 .2 255.255.255.0
 serial restart-delay 0
!
router ospf 1
 router-id 2.2.2 .2
 log-adjacency-changes
 network 12.1.1 .0 0.0.0.255 area 0
 
R3
interface Loopback0
 ip address 3.3.0 .3 255.255.255.0 secondary
 ip address 3.3.1 .3 255.255.255.0 secondary
 ip address 3.3.2 .3 255.255.255.0 secondary
 ip address 3.3.3 .3 255.255.255.0
 ip ospf network point-to-point
!
interface Serial1/0
 ip address 13.1.1 .3 255.255.255.0
 serial restart-delay 0
 no fair-queue
!
router ospf 1
 log-adjacency-changes
 network 3.3.0 .0 0.0.255.255 area 1
 network 13.1.1 .0 0.0.0.255 area 1
 
 
 
测试：
 
没有配置 lsa type3 过滤器之前 查看 r2 路由表
r2#sho ip route | begin Ga
Gateway of last resort is not set
 
     2.0.0 .0/24 is subnetted, 1 subnets
C       2.2.2 .0 is directly connected, Loopback0
     3.0.0 .0/24 is subnetted, 4 subnets
O IA    3.3.0 .0 [110/129] vi a 12.1.1 .1, 00:00:51, Serial2/0
O IA    3.3.1 .0 [110/129] vi a 12.1.1 .1, 00:00:57, Serial2/0
O IA    3.3.2 .0 [110/129] vi a 12.1.1 .1, 00:00:57, Serial2/0
O IA    3.3.3 .0 [110/129] vi a 12.1.1 .1, 00:00:45, Serial2/0
     12.0.0 .0/24 is subnetted, 1 subnets
C       12.1.1 .0 is directly connected, Serial2/0
     13.0.0 .0/24 is subnetted, 1 subnets
O IA    13.1.1 .0 [110/128] vi a 12.1.1 .1, 00:10:40, Serial2/0
 
配置过滤器   过滤掉 3.3.3 .0/24
r1(config)#ip prefix-list area1-out seq 10 deny 3.3.3 .0/24
r1(config)#ip prefix-list area1-out seq 15 permit 0.0.0 .0/0 le 32
r1(config-router)#area 1 filter-list prefix area1-out out
查看 r1 的数据库 area 0 中   没有 3.3.3 .3
1#sho ip os da
 
            OSPF Router with ID ( 1.1.1 .1) (Process ID 1)
 
                Router Link States (Area 0)
 
Link ID         ADV Router      Age         Seq#       Checksum Link count
1.1.1 .1         1.1.1 .1         11          0x80000006 0x 00F 080 2
2.2.2 .2         2.2.2 .2         1909        0x80000004 0x0091DD 2
 
                Summary Net Link States (Area 0)
 
Link ID         ADV Router      Age         Seq#       Checksum
3.3.0 .0         1.1.1 .1         406         0x80000004 0x 00A 648
3.3.1 .0         1.1.1 .1         411         0x80000001 0x 00A 14F
3.3.2 .0         1.1.1 .1         411         0x80000001 0x009659
13.1.1 .0        1.1.1 .1         11          0x80000004 0x0027BF
 
查看 r2 的路由表   没有 3.3.3 .0/24 的条目
r2#sho ip route | begin Ga
Gateway of last resort is not set
 
     2.0.0 .0/24 is subnetted, 1 subnets
C       2.2.2 .0 is directly connected, Loopback0
     3.0.0 .0/24 is subnetted, 3 subnets
O IA    3.3.0 .0 [110/129] vi a 12.1.1 .1, 00:07:55, Serial2/0
O IA    3.3.1 .0 [110/129] vi a 12.1.1 .1, 00:08:01, Serial2/0
O IA    3.3.2 .0 [110/129] vi a 12.1.1 .1, 00:08:01, Serial2/0
     12.0.0 .0/24 is subnetted, 1 subnets
C       12.1.1 .0 is directly connected, Serial2/0
     13.0.0 .0/24 is subnetted, 1 subnets
O IA    13.1.1 .0 [110/128] vi a 12.1.1 .1, 00:17:45, Serial2/0
 
－－－－－－－－－－－－－－－－－－－－－－－－－－
以下检验 area range 与 lsa 类型 3 过滤器之间的联系
If the area range command has been configured for this area, type 3 LSAs that correspond to the area range are sent to all other areas, only if at least one prefix in the area range matches an entry in the prefix list. If all specific prefixes are denied by the prefix list, type 3 LSAs that correspond to the area range command will not be sent to any other area. Prefixes that are not permitted by  
the prefix list are implicitly denied.―― 载自文档
在 R1 做汇总
r1(config-router)#area 1 range 3.3.0 .0 255.255.252.0
 
r2#sho ip route | be Ga
Gateway of last resort is not set
     2.0.0 .0/24 is subnetted, 1 subnets
C       2.2.2 .0 is directly connected, Loopback0
     3.0.0 .0/22 is subnetted, 1 subnets
O IA    3.3.0 .0 [110/129] vi a 12.1.1 .1, 00:04:31, Serial2/0
     12.0.0 .0/24 is subnetted, 1 subnets
C       12.1.1 .0 is directly connected, Serial2/0
     13.0.0 .0/24 is subnetted, 1 subnets
O IA    13.1.1 .0 [110/128] vi a 12.1.1 .1, 00:23:50, Serial2/0
 
在 r1 上增加几句 prefix-list 把 3.3.0 .0 所有网段都排除
r1(config)#ip prefix-list area1-out seq 11 deny 3.3.0 .0/24
r1(config)#ip prefix-list area1-out seq 12 deny 3.3.1 .0/24
r1(config)#ip prefix-list area1-out seq 13 deny 3.3.2 .0/24
 
查看 r2 路由表，那条汇总路由 3.0.0 .0/22 没有了
r2#sho ip route | be Ga
Gateway of last resort is not set
 
     2.0.0 .0/24 is subnetted, 1 subnets
C       2.2.2 .0 is directly connected, Loopback0
     12.0.0 .0/24 is subnetted, 1 subnets
C       12.1.1 .0 is directly connected, Serial2/0
     13.0.0 .0/24 is subnetted, 1 subnets
O IA    13.1.1 .0 [110/128] vi a 12.1.1 .1, 00:31:35, Serial2/0
结论：如果所有明细的路由都被禁止了，汇总也会没掉
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