OSPF ABR Type 3 LSA Filtering
Document ID: 00007
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目录
提要
正文
TOPO
如下
基本配置如下
验证
附注
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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
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.�D�D
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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