华为路由器OSPF虚链路配置（三）

• 我们知道在OSPF配置当中，非骨干区域必须和骨干区域直接相连，若不与骨干区域直接相连，则需要配置虚链路，本篇文章主要介绍OSPF虚链路配置命令。

    实验配置如下图：
  

  实验说明如下：

1.路由器R1、R2在0区域，路由器R2、R3、R4在234区域，路由器R4、R5在45区域。 2.45区域没有与骨干区域直接相连，因此在不引入外部路由的情况下，需要在路由R2、R4上配置虚链路。

第一步，实验基本配置如下：

R1 system-view sysname R1 user-interface console 0 idle-timeout 1000 quit interface GigabitEthernet0/0/2 ip address 192.168.1.254 255.255.255.0 interface GigabitEthernet0/0/1 ip address 192.168.17.1 255.255.255.0 interface GigabitEthernet0/0/0 ip address 192.168.12.1 255.255.255.0 quit R2 system-view sysname R2 interface GigabitEthernet0/0/1 ip address 192.168.12.2 255.255.255.0 interface GigabitEthernet0/0/0 ip address 192.168.23.2 255.255.255.0 quit R3 system-view sysname R3 interface GigabitEthernet0/0/1 ip address 192.168.23.3 255.255.255.0 interface GigabitEthernet0/0/0 ip address 192.168.34.3 255.255.255.0 quit R4 system-view sysname R4 interface GigabitEthernet0/0/1 ip address 192.168.34.4 255.255.255.0 interface GigabitEthernet0/0/0 ip address 192.168.45.4 255.255.255.0 quit R5 system-view sysname R5 interface GigabitEthernet0/0/1 ip address 192.168.45.5 255.255.255.0 interface GigabitEthernet0/0/2 ip address 192.168.5.254 255.255.255.0 interface GigabitEthernet0/0/0 ip address 100.1.1.5 255.255.255.0 quit

第二步，配置OSPF;

配置命令如下： R1 ospf 1 router-id 1.1.1.1 area 0 network 192.168.12.0 0.0.0.255 network 192.168.1.0 0.0.0.255 R2 ospf 1 router-id 2.2.2.2 area 0 network 192.168.12.0 0.0.0.255 area 234 network 192.168.23.0 0.0.0.255 R3 ospf 1 router-id 3.3.3.3 area 234 network 192.168.23.0 0.0.0.255 network 192.168.34.0 0.0.0.255 R4 ospf 1 router-id 4.4.4.4 area 234 network 192.168.34.0 0.0.0.255 area 45 network 192.168.45.0 0.0.0.255 R5 ospf 1 router-id 5.5.5.5 area 45 network 192.168.45.0 0.0.0.255 network 192.168.5.0 0.0.0.255 quit

查看R1的路由表，如下：

[R1]display ip routing-table protocol ospf Route Flags: R - relay, D - download to fib Public routing table : OSPF Destinations : 2 Routes : 2

OSPF routing table status : <Active> Destinations : 2 Routes : 2

Destination/Mask Proto Pre Cost Flags NextHop Interface

192.168.23.0/24 OSPF 10 2 D 192.168.12.2 GigabitEthernet 0/0/0 192.168.34.0/24 OSPF 10 3 D 192.168.12.2 GigabitEthernet 0/0/0

 分析：由于45区域没有与骨干0区域直接相连，因此R1上面没有45区域的路由信息。
	 
第三步，配置虚链路，即vlink-peer。

分别在R2、R4上配置vlink-peer： R2 ospf 1 area 234 vlink-peer 4.4.4.4 R4 ospf 1 area 234 vlink-peer 2.2.2.2

验证：
	查看R1的路由表，如下：

[R1]display ip routing-table protocol ospf Route Flags: R - relay, D - download to fib Public routing table : OSPF Destinations : 4 Routes : 4

OSPF routing table status : <Active> Destinations : 4 Routes : 4

Destination/Mask Proto Pre Cost Flags NextHop Interface

192.168.5.0/24  OSPF    10   5           D   192.168.12.2    GigabitEthernet

0/0/0 192.168.23.0/24 OSPF 10 2 D 192.168.12.2 GigabitEthernet 0/0/0 192.168.34.0/24 OSPF 10 3 D 192.168.12.2 GigabitEthernet 0/0/0 192.168.45.0/24 OSPF 10 4 D 192.168.12.2 GigabitEthernet 0/0/0

OSPF routing table status : <Inactive> Destinations : 0 Routes : 0 测试PC1、PC2的网络联通性：

总结
	    查看R4的路由信息：

[R4]display ospf brief

 OSPF Process 1 with Router ID 4.4.4.4
	 OSPF Protocol Information

RouterID: 4.4.4.4 Border Router: AREA Multi-×××-Instance is not enabled Global DS-TE Mode: Non-Standard IETF Mode Graceful-restart capability: disabled Helper support capability : not configured Applications Supported: MPLS Traffic-Engineering Spf-schedule-interval: max 10000ms, start 500ms, hold 1000ms Default ASE parameters: Metric: 1 Tag: 1 Type: 2 Route Preference: 10 ASE Route Preference: 150 SPF Computation Count: 14
RFC 1583 Compatible Retransmission limitation is disabled Area Count: 3 Nssa Area Count: 0 ExChange/Loading Neighbors: 0 Process total up interface count: 3 Process valid up interface count: 2

 分析得出：
	  R4路由状态以变为区域ABR，即虚链路使得R4直接与骨干区域相连。