（OSPF实验）OSPF ABR Typ

2023-01-31 05:01:30 实验 OSPF Typ
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] via 12.1.1.1, 00:00:51, Serial2/0

O IA    3.3.1.0 [110/129] via 12.1.1.1, 00:00:57, Serial2/0

O IA    3.3.2.0 [110/129] via 12.1.1.1, 00:00:57, Serial2/0

O IA    3.3.3.0 [110/129] via 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] via 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 0x00F080 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 0x00A648

3.3.1.0         1.1.1.1         411         0x80000001 0x00A14F

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] via 12.1.1.1, 00:07:55, Serial2/0

O IA    3.3.1.0 [110/129] via 12.1.1.1, 00:08:01, Serial2/0

O IA    3.3.2.0 [110/129] via 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] via 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] via 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] via 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] via 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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