OSPF特殊区域配置详解-优快云博客

Configuring OSPF Special Area Types

Types of Areas

Stub and Totally Stub Area Rules

Hello 1,hello

2,area

3,atuh

4stub标识

作用是否下放默认路由

Stub 过滤LSA4/5 是（LSA3）Seed cost =1

Totally Stub 过滤LSA3//4/5 是（LSA3）Seed cost =1

NSSA 过滤LSA4/5 否（default:LSA7）Cost 1

Totally NSSA 过滤LSA3/4/5 是 (no-summary)Cost=1

1，stub区域

R4#show ip ospf database              

            OSPF Router with ID (4.4.4.4) (Process ID 110)

                Router Link States (Area 1)【LSA1】

Link ID         ADV Router      Age         Seq#       Checksum Link count
2.2.2.2         2.2.2.2         1316        0x80000003 0x0066E4 2
4.4.4.4         4.4.4.4         1320        0x80000005 0x00BD61 3

                Summary Net Link States (Area 1)【LSA3】

Link ID         ADV Router      Age         Seq#       Checksum
1.1.1.1         2.2.2.2         1240        0x80000001 0x00AB44
2.2.2.2         2.2.2.2         1388        0x80000001 0x00FA31
3.3.3.3         2.2.2.2         708         0x80000001 0x00D1D5
12.1.1.0        2.2.2.2         1398        0x80000001 0x001CCA
13.1.1.0        2.2.2.2         1250        0x80000001 0x009114

                Summary ASB Link States (Area 1)【LSA4】

Link ID         ADV Router      Age         Seq#       Checksum
3.3.3.3         2.2.2.2         723         0x80000001 0x00B9ED

                Type-5 AS External Link States【LSA5】

Link ID         ADV Router      Age         Seq#       Checksum Tag
5.0.0.0         3.3.3.3         730         0x80000001 0x004C43 0
35.1.1.0        3.3.3.3         730         0x80000001 0x00ADC1 0

把area1配置成sub,区域中所有路由器都要起sub

R4(config)#router ospf 110
R4(config-router)#area 1 stub

R2(config)#router ospf 110
R2(config-router)#area 1 stub

E2路由没有了，产生一条默认路由指向R2。



O*IA  0.0.0.0/0 [110/65] via 24.1.1.2, 00:01:03, Serial2/0
      1.0.0.0/32 is subnetted, 1 subnets
O IA     1.1.1.1 [110/129] via 24.1.1.2, 00:01:03, Serial2/0
      2.0.0.0/32 is subnetted, 1 subnets
O IA     2.2.2.2 [110/65] via 24.1.1.2, 00:01:03, Serial2/0
      3.0.0.0/32 is subnetted, 1 subnets
O IA     3.3.3.3 [110/193] via 24.1.1.2, 00:01:03, Serial2/0
      12.0.0.0/24 is subnetted, 1 subnets
O IA     12.1.1.0 [110/128] via 24.1.1.2, 00:01:03, Serial2/0
      13.0.0.0/24 is subnetted, 1 subnets
O IA     13.1.1.0 [110/192] via 24.1.1.2, 00:01:03, Serial2/0

LSA4 和LSA5都被过滤了

R4#show ip ospf database 

            OSPF Router with ID (4.4.4.4) (Process ID 110)

                Router Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum Link count
2.2.2.2         2.2.2.2         41          0x80000006 0x007ECB 2
4.4.4.4         4.4.4.4         194         0x80000007 0x00D747 3

                Summary Net Link States (Area 1)

Link ID         ADV Router      Age         Seq#       Checksum
0.0.0.0         2.2.2.2         196         0x80000001 0x0075C0
1.1.1.1         2.2.2.2         196         0x80000002 0x00C729
2.2.2.2         2.2.2.2         41          0x80000003 0x001517
3.3.3.3         2.2.2.2         196         0x80000002 0x00EDBA
12.1.1.0        2.2.2.2         41          0x80000003 0x0036B0
13.1.1.0        2.2.2.2         196         0x80000002 0x00ADF8

下放3类默认路由，

使用Stub区域

配置Stub区域

修改默认cost值

R2(config-router)#area 1 default-cost 5

cost 值变为69,64+5

O*IA  0.0.0.0/0 [110/69] via 24.1.1.2, 00:00:06, Serial2/0

2，Totally Stub

只在ABR上配置

R2(config-router)#area  1 stub  no-summary

只剩下一条默认ospf路由

R4#show ip route ospf
O*IA  0.0.0.0/0 [110/69] via 24.1.1.2, 00:01:09, Serial2

使用完全末节区域

配置末节区域

3，NSSA（Not-So-Stubby Areas）完全非末节区域

NSSA过滤左边的LSA5,R1会把LSA7转来LSA5

R1 上的路由

R1#show ip route | i E2
       E1 - OSPF external type 1, E2 - OSPF external type 2
O E2  5.0.0.0/8 [110/20] via 13.1.1.3, 00:28:33, Serial2/0
O E2     35.1.1.0 [110/20] via 13.1.1.3, 00:28:53, Serial2/0
O E2     44.4.4.0 [110/20] via 12.1.1.2, 00:00:09, Serial2/1

将area2配置成NSSA区域，R1和R2上都需要配置

R1(config-router)#area 2 nssa

R3(config-router)#area 2 nssa

R3上没有44.4.4.0/24的路由，必须手工配置，在R1上配置。

R3#show ip route ospf
      1.0.0.0/32 is subnetted, 1 subnets
O IA     1.1.1.1 [110/65] via 13.1.1.1, 00:01:37, Serial2/1
      2.0.0.0/32 is subnetted, 1 subnets
O IA     2.2.2.2 [110/129] via 13.1.1.1, 00:01:37, Serial2/1
      4.0.0.0/32 is subnetted, 1 subnets
O IA     4.4.4.4 [110/193] via 13.1.1.1, 00:01:37, Serial2/1
      12.0.0.0/24 is subnetted, 1 subnets
O IA     12.1.1.0 [110/128] via 13.1.1.1, 00:01:37, Serial2/1
      24.0.0.0/24 is subnetted, 1 subnets
O IA     24.1.1.0 [110/192] via 13.1.1.1, 00:01:37, Serial2/1

在R1上配置，下放默认路由（nssa第一个选项）

R1(config-router)#area 2 nssa default-information-originate

R3上多了一条N2默认路由

R3#show ip route ospf
O*N2  0.0.0.0/0 [110/1] via 13.1.1.1, 00:01:59, Serial2/1
      1.0.0.0/32 is subnetted, 1 subnets
O IA     1.1.1.1 [110/65] via 13.1.1.1, 00:05:44, Serial2/1
      2.0.0.0/32 is subnetted, 1 subnets
O IA     2.2.2.2 [110/129] via 13.1.1.1, 00:05:44, Serial2/1
      4.0.0.0/32 is subnetted, 1 subnets
O IA     4.4.4.4 [110/193] via 13.1.1.1, 00:05:44, Serial2/1
      12.0.0.0/24 is subnetted, 1 subnets
O IA     12.1.1.0 [110/128] via 13.1.1.1, 00:05:44, Serial2/1
      24.0.0.0/24 is subnetted, 1 subnets
O IA     24.1.1.0 [110/192] via 13.1.1.1, 00:05:44, Serial2/1

LSA7存在某个区域，LSA5不属于任何区域

R3#show ip ospf database 

            OSPF Router with ID (3.3.3.3) (Process ID 110)

                Router Link States (Area 2)

Link ID         ADV Router      Age         Seq#       Checksum Link count
1.1.1.1         1.1.1.1         501         0x80000004 0x00E084 2
3.3.3.3         3.3.3.3         497         0x80000005 0x00D26B 3

                Summary Net Link States (Area 2)

Link ID         ADV Router      Age         Seq#       Checksum
1.1.1.1         1.1.1.1         526         0x80000003 0x00E843
2.2.2.2         1.1.1.1         526         0x80000003 0x003DAA
4.4.4.4         1.1.1.1         526         0x80000002 0x00653B
12.1.1.0        1.1.1.1         526         0x80000003 0x00DB07
24.1.1.0        1.1.1.1         526         0x80000003 0x00C1D4

                Type-7 AS External Link States (Area 2)

Link ID         ADV Router      Age         Seq#       Checksum Tag
0.0.0.0         1.1.1.1         264         0x80000001 0x00EEBE 0
5.0.0.0         3.3.3.3         502         0x80000001 0x004E2B 0
35.1.1.0        3.3.3.3         502         0x80000001 0x00AFA9 0

R3能访问44.4.4.0/24网段

R3#ping 44.4.4.4
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 44.4.4.4, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 26/26/27 ms

R4上有ripRIP上所的的路由信息

R4#show ip route ospf
      1.0.0.0/32 is subnetted, 1 subnets
O IA     1.1.1.1 [110/129] via 24.1.1.2, 00:19:00, Serial2/0
      2.0.0.0/32 is subnetted, 1 subnets
O IA     2.2.2.2 [110/65] via 24.1.1.2, 00:19:00, Serial2/0
      3.0.0.0/32 is subnetted, 1 subnets
O IA     3.3.3.3 [110/193] via 24.1.1.2, 00:12:38, Serial2/0
O E2  5.0.0.0/8 [110/20] via 24.1.1.2, 00:12:37, Serial2/0
      12.0.0.0/24 is subnetted, 1 subnets
O IA     12.1.1.0 [110/128] via 24.1.1.2, 00:19:00, Serial2/0
      13.0.0.0/24 is subnetted, 1 subnets
O IA     13.1.1.0 [110/192] via 24.1.1.2, 00:19:00, Serial2/0
      35.0.0.0/24 is subnetted, 1 subnets
O E2     35.1.1.0 [110/20] via 24.1.1.2, 00:12:37, Serial2/0

R1即是ABR,也是ASBR,

ASBR能够产生LSA5的路由器，就是ASBR。

R2#show ip ospf border-routers 
i 4.4.4.4 [64] via 24.1.1.4, Serial2/1, ASBR, Area 1, SPF 7
i 1.1.1.1 [64] via 12.1.1.1, Serial2/0, ABR/ASBR, Area 0, SPF 6

4，Totally NSSA

（nssa第二个选项）

过滤LSA3/4/5，并产生3类默认路由

R1(config-router)#area 2 nssa no-summary

3类默认路由

R3#show ip route ospf
O*IA  0.0.0.0/0 [110/65] via 13.1.1.1, 00:01:32, Serial2/1

在R1上增加一个外部

R4有100.1.1.0/24的路由

R4#ping 100.1.1.1

      1.0.0.0/32 is subnetted, 1 subnets
O IA     1.1.1.1 [110/129] via 24.1.1.2, 01:02:39, Serial2/0
      2.0.0.0/32 is subnetted, 1 subnets
O IA     2.2.2.2 [110/65] via 24.1.1.2, 01:02:39, Serial2/0
      3.0.0.0/32 is subnetted, 1 subnets
O IA     3.3.3.3 [110/193] via 24.1.1.2, 00:56:17, Serial2/0
O E2  5.0.0.0/8 [110/20] via 24.1.1.2, 00:56:16, Serial2/0
      12.0.0.0/24 is subnetted, 1 subnets
O IA     12.1.1.0 [110/128] via 24.1.1.2, 01:02:39, Serial2/0
      13.0.0.0/24 is subnetted, 1 subnets
O IA     13.1.1.0 [110/192] via 24.1.1.2, 01:02:39, Serial2/0
      35.0.0.0/24 is subnetted, 1 subnets
O E2     35.1.1.0 [110/20] via 24.1.1.2, 00:56:16, Serial2/0
      100.0.0.0/24 is subnetted, 1 subnets
O E2     100.1.1.0 [110/20] via 24.1.1.2, 00:18:20, Serial2/0

R3上有100.1.1.0/24的路由，可以过滤掉。

R3#show ip route ospf
O*IA  0.0.0.0/0 [110/65] via 13.1.1.1, 00:12:45, Serial2/1
      100.0.0.0/24 is subnetted, 1 subnets
O N2     100.1.1.0 [110/20] via 13.1.1.1, 00:06:19, Serial2/11, 00:02:07, Serial2/1

过滤命令

nssa 第三个选项

 area 2 nssa no-redistribution default-information-originate no-summary
 redistribute rip subnets

R3#show ip route ospf
O*IA  0.0.0.0/0 [110/65] via 13.1.1.1, 00:01:17, Serial2/1

最好的，no-redistribution no-summary

——————————————————————————————————————————————————————

虚链路，不规则区域

三种解决方案

1，多进程双向重分布

R3能否学到R5环回口的路由？可以学到。

R1能否学到R5环回口的路由？不能学到。

R3开两个ospf进程，把左右两边的路由重分布到各自的进行中。

R3#show run | b r o
router ospf 110
 router-id 3.3.3.3
 redistribute ospf 100 subnets
 network 3.3.3.0 0.0.0.255 area 2
 network 13.1.1.0 0.0.0.255 area 2
!
router ospf 100
 router-id 3.3.3.33
 redistribute ospf 110 subnets
 network 35.1.1.0 0.0.0.255 area 3
!
ip forward-protocol nd

R5#show ip route ospf
      1.0.0.0/32 is subnetted, 1 subnets
O E2     1.1.1.1 [110/65] via 35.1.1.3, 00:01:18, Serial2/1
      2.0.0.0/32 is subnetted, 1 subnets
O E2     2.2.2.2 [110/129] via 35.1.1.3, 00:01:18, Serial2/1
      3.0.0.0/24 is subnetted, 1 subnets
O E2     3.3.3.0 [110/1] via 35.1.1.3, 00:01:18, Serial2/1
      4.0.0.0/32 is subnetted, 1 subnets
O E2     4.4.4.4 [110/193] via 35.1.1.3, 00:01:18, Serial2/1
      12.0.0.0/24 is subnetted, 1 subnets
O E2     12.1.1.0 [110/128] via 35.1.1.3, 00:01:18, Serial2/1
      13.0.0.0/24 is subnetted, 1 subnets
O E2     13.1.1.0 [110/64] via 35.1.1.3, 00:01:18, Serial2/1
      24.0.0.0/24 is subnetted, 1 subnets
O E2     24.1.1.0 [110/192] via 35.1.1.3, 00:01:18, Serial2/1
      100.0.0.0/24 is subnetted, 1 subnets
O E2     100.1.1.0 [110/20] via 35.1.1.3, 00:01:18, Serial2/1

R4#show ip route ospf 
      1.0.0.0/32 is subnetted, 1 subnets
O IA     1.1.1.1 [110/129] via 24.1.1.2, 00:15:53, Serial2/0
      2.0.0.0/32 is subnetted, 1 subnets
O IA     2.2.2.2 [110/65] via 24.1.1.2, 00:15:53, Serial2/0
      3.0.0.0/32 is subnetted, 1 subnets
O IA     3.3.3.3 [110/193] via 24.1.1.2, 00:15:53, Serial2/0
      5.0.0.0/32 is subnetted, 1 subnets
O E2     5.5.5.5 [110/65] via 24.1.1.2, 00:02:28, Serial2/0
      12.0.0.0/24 is subnetted, 1 subnets
O IA     12.1.1.0 [110/128] via 24.1.1.2, 00:15:53, Serial2/0
      13.0.0.0/24 is subnetted, 1 subnets
O IA     13.1.1.0 [110/192] via 24.1.1.2, 00:15:53, Serial2/0
      35.0.0.0/24 is subnetted, 1 subnets
O E2     35.1.1.0 [110/64] via 24.1.1.2, 00:02:28, Serial2/0
      100.0.0.0/24 is subnetted, 1 subnets
O E2     100.1.1.0 [110/20] via 24.1.1.2, 00:15:53, Serial2/0

2.Tunnel

R1上启一个Tunnel1口

R1(config)#interface  Tunnel 1
R1(config-if)#tunnel source 13.1.1.1
R1(config-if)#tunnel destination 13.1.1.3
R1(config-if)#ip address 172.16.1.1 255.255.255.0

R1上将172.16.1.0/24通告进area 0

R3上上启一个Tunnel1口

R3(config)#int Tunnel 3
R3(config-if)#tunnel source 13.1.1.3
R3(config-if)#tunnel destination 13.1.1.1
R3(config-if)#ip add 172.16.1.2 255.255.255.0

R3上将172.16.1.0/24通告进area 0

R3(config-router)#network 172.16.1.0 0.0.0.255 area 0

查看R5上的路由

R5#show ip route ospf 
      1.0.0.0/32 is subnetted, 1 subnets
O IA     1.1.1.1 [110/1065] via 35.1.1.3, 01:52:28, Serial2/1
      2.0.0.0/32 is subnetted, 1 subnets
O IA     2.2.2.2 [110/1129] via 35.1.1.3, 01:52:28, Serial2/1
      4.0.0.0/32 is subnetted, 1 subnets
O IA     4.4.4.4 [110/1193] via 35.1.1.3, 01:52:28, Serial2/1
      12.0.0.0/24 is subnetted, 1 subnets
O IA     12.1.1.0 [110/1128] via 35.1.1.3, 01:52:28, Serial2/1
      24.0.0.0/24 is subnetted, 1 subnets
O IA     24.1.1.0 [110/1192] via 35.1.1.3, 01:52:28, Serial2/1
      172.16.0.0/24 is subnetted, 1 subnets
O IA     172.16.1.0 [110/1064] via 35.1.1.3, 01:52:28, Serial2/1

查看R4上的路由

R4#show ip route ospf
      1.0.0.0/32 is subnetted, 1 subnets
O IA     1.1.1.1 [110/129] via 24.1.1.2, 02:22:42, Serial2/0
      2.0.0.0/32 is subnetted, 1 subnets
O IA     2.2.2.2 [110/65] via 24.1.1.2, 02:22:42, Serial2/0
      5.0.0.0/32 is subnetted, 1 subnets
O IA     5.5.5.5 [110/1193] via 24.1.1.2, 01:50:06, Serial2/0
      12.0.0.0/24 is subnetted, 1 subnets
O IA     12.1.1.0 [110/128] via 24.1.1.2, 02:22:42, Serial2/0
      13.0.0.0/24 is subnetted, 1 subnets
O IA     13.1.1.0 [110/192] via 24.1.1.2, 02:22:42, Serial2/0
      35.0.0.0/24 is subnetted, 1 subnets
O IA     35.1.1.0 [110/1192] via 24.1.1.2, 01:50:06, Serial2/0
      172.16.0.0/24 is subnetted, 1 subnets
O IA     172.16.1.0 [110/1128] via 24.1.1.2, 01:53:05, Serial2/0

3 虚链路

配置

R1上在区域2配置虚链路

R1(config-router)#area 2 virtual-link 3.3.3.3

R3上在区域2配置虚链路

R3(config-router)#area 2 virtual-link 1.1.1.1

R3#show ip ospf neighbor 

Neighbor ID     Pri   State           Dead Time   Address         Interface
1.1.1.1           0   FULL/  -           -        13.1.1.1        OSPF_VL0
1.1.1.1           0   FULL/  -        00:00:38    13.1.1.1        Serial2/1
5.5.5.5           0   FULL/  -        00:00:35    35.1.1.5        Serial2/0

检查虚链路是否起来，关注 Adjacency State FULL (Hello suppressed)

R3#show ip ospf virtual-links 
Virtual Link OSPF_VL0 to router 1.1.1.1 is up
  Run as demand circuit
  DoNotAge LSA allowed.
  Transit area 2, via interface Serial2/1
 Topology-MTID    Cost    Disabled     Shutdown      Topology Name
        0           64        no          no            Base
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    Hello due in 00:00:00
    Adjacency State FULL (Hello suppressed)
    Index 1/3, retransmission queue length 0, number of retransmission 0
    First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
    Last retransmission scan length is 0, maximum is 0
    Last retransmission scan time is 0 msec, maximum is 0 msec

查看路由表

R5#show ip route ospf 

      1.0.0.0/32 is subnetted, 1 subnets
O IA     1.1.1.1 [110/129] via 35.1.1.3, 00:06:23, Serial2/1
      2.0.0.0/32 is subnetted, 1 subnets
O IA     2.2.2.2 [110/193] via 35.1.1.3, 00:06:23, Serial2/1
      4.0.0.0/32 is subnetted, 1 subnets
O IA     4.4.4.4 [110/257] via 35.1.1.3, 00:06:23, Serial2/1
      12.0.0.0/24 is subnetted, 1 subnets
O IA     12.1.1.0 [110/192] via 35.1.1.3, 00:06:23, Serial2/1
      13.0.0.0/24 is subnetted, 1 subnets
O IA     13.1.1.0 [110/128] via 35.1.1.3, 00:06:33, Serial2/1
      24.0.0.0/24 is subnetted, 1 subnets
O IA     24.1.1.0 [110/256] via 35.1.1.3, 00:06:23, Serial2/1

通过Router ID 找直连路由

OSPF Authentication

1，LInk 认证

a,明文

R2和R4

声明密钥

R4(config)#int s2/0
R4(config-if)#ip ospf authentication-key ?
  <0-7>  Encryption type (0 for not yet encrypted, 7 for proprietary)
  LINE   The OSPF password (key) (maximum 8 characters)

R4(config-if)#ip ospf authentication-key cisco

使密钥生效

R4(config-if)#ip ospf authentication

明文

interface Serial2/0
 ip address 24.1.1.4 255.255.255.0
 ip ospf authentication
 ip ospf authentication-key cisco

密文

interface Serial2/0
 ip address 24.1.1.4 255.255.255.0
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 cisco

2，区域认证

明文

密钥在接口下声明，生效在ospf进行下配置

R4配置

R4(config)#int s2/0
R4(config-if)#ip ospf authentication-key cisco
R4(config-if)#router ospf 110
R4(config-router)#area 1 authentication

R2配置

R2(config-if)#int s2/1
R2(config-if)#ip ospf authentication-key cisco
R2(config-if)#router ospf 110
R2(config-router)#area 1 authentication

密文

R4配置

R4(config)#int s2/0
R4(config-if)#ip ospf message-digest-key 1 md5 cisco
R4(config-if)#router ospf 110
R4(config-router)#area 1 authentication message-digest

R2配置

R2(config)#int s2/1
R2(config-if)#ip ospf message-digest-key 1 md5 cisco
R2(config-if)#router ospf 110
R2(config-router)#area 1 authentication message-digest

3，虚链路认证

明文

R1(config)#router ospf 110
R1(config-router)#area 2 virtual-link 3.3.3.3 authentication-key cisco
R1(config-router)#area 2 virtual-link 3.3.3.3 authentication

密文

R1(config)#router ospf 110
R1(config-router)#area 2 virtual-link 3.3.3.3 message-digest-key 1 md5 cisco
R1(config-router)#area 2 virtual-link 3.3.3.3 authentication message-digest

R3 虚链路后做起密钥。在区域0做认证

负载均衡：

R1(config-router)#maximum-paths ?
<1-32> Number of paths

被动接口，不收发OSPF报文