3.4 OSPF配置详解

4.OSPF的COST值

1）基本配置

[R1]ospf 1 router-id 1.1.1.1
[R1-ospf-1]area 0
[R1-ospf-1-area-0.0.0.0]network 1.1.1.1 0.0.0.0
[R1-ospf-1-area-0.0.0.0]network 13.1.1.0 0.255.255.255 
[R1-ospf-1-area-0.0.0.0]network 192.168.12.0 0.0.0.255

[R2]ospf 1 router-id  2.2.2.2
[R2-ospf-1]area 0
[R2-ospf-1-area-0.0.0.0]network 2.2.2.2 0.0.0.0
[R2-ospf-1-area-0.0.0.0]network 192.168.12.0 0.0.0.255
[R2-ospf-1-area-0.0.0.0]network 23.1.1.0 0.255.255.255

[R3]ospf 1 router-id 3.3.3.3
[R3-ospf-1]area 0
[R3-ospf-1-area-0.0.0.0]network 3.3.3.3 0.0.0.0
[R3-ospf-1-area-0.0.0.0]network 13.1.1.0 0.255.255.255
[R3-ospf-1-area-0.0.0.0]network 23.1.1.0 0.255.255.255

2）查看R3的OSPF路由表，前往192.168.12.0的路由在R1、R2实现负载分担。

[R3]display  ip routing-table protocol  ospf 
Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface
1.1.1.1/32  OSPF    10   1           D   13.1.1.1        GigabitEthernet0/0/0
2.2.2.2/32  OSPF    10   1           D   23.1.1.2        GigabitEthernet0/0/1
192.168.12.0/24  OSPF    10   2           D   13.1.1.1        GigabitEthernet0/0/0
           OSPF    10   2           D   23.1.1.2     GigabitEthernet0/0/1

3）修改R3的G0/0/1口的路由COST值，查看路由表，前往192.168.12.0/24路径通过的路由器为R1

[R3]interface GigabitEthernet 0/0/1
[R3-GigabitEthernet0/0/1]ospf cost 100
[R3]display ip routing-table protocol ospf 
Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface
1.1.1.1/32  OSPF    10   1           D   13.1.1.1        GigabitEthernet0/0/0
2.2.2.2/32  OSPF    10   2           D   13.1.1.1        GigabitEthernet0/0/0
192.168.12.0/24  OSPF    10   2           D   13.1.1.1        GigabitEthernet0/0/0

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