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OSPF虚链路(virtual-link)配置实例 + 详细验证过程

更新时间:2022-09-04 18:07:43











本文转自 ciscodocu51CTO博客,原文链接:http://blog.51cto.com/ciscodocu/52828OSPF虚链路(virtual-link)配置实例 + 详细验证过程

这个配置将验证一个OSPF虚电路(Virtual-Link)的过程,重点在观察虚链路连接的临时网络与正常区域间路由有何区别。上图中区域4(area 4)没有和area 0直接相连。在R2与R3之间配置了一条虚链路。
 
// R1 //
int lo0
  ip ad 1.1.1.1 255.255.255.0
 
int e0
  ip ad 192.1.1.1 255.255.255.0
 
router os 1
  network 192.1.1.0 0.0.0.255 area 0
 
 
// R2 //
int lo0
  ip ad 2.2.2.2 255.255.255.0
 
int e0
  ip ad 192.1.1.2 255.255.255.0
 
int e1
  ip ad 193.1.1.2 255.255.255.0
 
router os 1
  network 192.1.1.0 0.0.0.255 area 0
  network 193.1.1.0 0.0.0.255 area 1
 
 
// R3 //
int lo0
  ip ad 3.3.3.3 255.255.255.0
 
int e1
  ip ad 193.1.1.3 255.255.255.0
 
int e0
  ip ad 194.1.1.3 255.255.255.0
 
router os 1
  network 193.1.1.0 0.0.0.255 area 1
  network 194.1.1.0 0.0.0.255 area 4
 
 
// R4 //
int lo0
  ip ad 4.4.4.4 255.255.255.0
 
int e0
  ip ad 194.1.1.4 255.255.255.0
 
router os 1
  network 194.1.1.0 0.0.0.255 area 4
 
 
 
基本配置完成后,我们在每台路由器上分别来验证一下:
r1#sh ip os nei
Neighbor ID     Pri   State           Dead Time   Address         Interface
2.2.2.2           1   FULL/BDR        00:00:33    192.1.1.2       Ethernet0/0
r1#
r1#sh ip ro
     1.0.0.0/24 is subnetted, 1 subnets
C       1.1.1.0 is directly connected, Loopback0
O IA 193.1.1.0/24 [110/20] via 192.1.1.2, 00:00:19, Ethernet0/0
C    192.1.1.0/24 is directly connected, Ethernet0/0
//注意R1上有关于193.1.1.0的路由条目,是属于IA类型(域间路由)
 
r2#sh ip os nei
Neighbor ID     Pri   State           Dead Time   Address         Interface
1.1.1.1           1   FULL/DR         00:00:35    192.1.1.1       Ethernet0/0
3.3.3.3           1   FULL/BDR        00:00:35    193.1.1.3       Ethernet1/0
r2#
r2#
r2#sh ip ro
     2.0.0.0/24 is subnetted, 1 subnets
C       2.2.2.0 is directly connected, Loopback0
C    193.1.1.0/24 is directly connected, Ethernet1/0
C    192.1.1.0/24 is directly connected, Ethernet0/0
 
 
r3#sh ip os nei
Neighbor ID     Pri   State           Dead Time   Address         Interface
2.2.2.2           1   FULL/DR         00:00:32    193.1.1.2       Ethernet1/0
4.4.4.4           1   FULL/DR         00:00:34    194.1.1.4       Ethernet0/0
r3#sh ip ro
     3.0.0.0/24 is subnetted, 1 subnets
C       3.3.3.0 is directly connected, Loopback0
C    193.1.1.0/24 is directly connected, Ethernet1/0
O IA 192.1.1.0/24 [110/20] via 193.1.1.2, 00:02:49, Ethernet1/0
C    194.1.1.0/24 is directly connected, Ethernet0/0
//注意R3中有关于192.1.1.0的路由是属于IA类型(域间路由)
 
r4#sh ip os nei
Neighbor ID     Pri   State           Dead Time   Address         Interface
3.3.3.3           1   FULL/BDR        00:00:33    194.1.1.3       Ethernet0/0
r4#sh ip ro
     4.0.0.0/24 is subnetted, 1 subnets
C       4.4.4.0 is directly connected, Loopback0
C    194.1.1.0/24 is directly connected, Ethernet0/0
//R4上没有关于AREA 0内的任何路由信息
 
 
 
 
 
我们下面在R2、R3上添加Virtual-link的配置:
R2:
router os 1
  area 1 virtual-link 3.3.3.3
 
R3:
router os 1
  area 1 virtual-link 2.2.2.2
 
 
 
 
对比之前的路由信息,看有何区别:
r1#sh ip ro
     1.0.0.0/24 is subnetted, 1 subnets
C       1.1.1.0 is directly connected, Loopback0
O IA 193.1.1.0/24 [110/20] via 192.1.1.2, 00:00:01, Ethernet0/0
C    192.1.1.0/24 is directly connected, Ethernet0/0
O IA 194.1.1.0/24 [110/30] via 192.1.1.2, 00:00:01, Ethernet0/0
//多了一条194网段的路由,类型IA(区域间)
 

r2#sh ip ro
     2.0.0.0/24 is subnetted, 1 subnets
C       2.2.2.0 is directly connected, Loopback0
C    193.1.1.0/24 is directly connected, Ethernet1/0
C    192.1.1.0/24 is directly connected, Ethernet0/0
O IA 194.1.1.0/24 [110/20] via 193.1.1.3, 00:00:06, Ethernet1/0
//多了一条194网段路由,类型为IA(区域间)
 
r3#sh ip ro
     3.0.0.0/24 is subnetted, 1 subnets
C       3.3.3.0 is directly connected, Loopback0
C    193.1.1.0/24 is directly connected, Ethernet1/0
O    192.1.1.0/24 [110/20] via 193.1.1.2, 00:02:56, Ethernet1/0
C    194.1.1.0/24 is directly connected, Ethernet0/0
//R3的192路由原本为IA类型(区域间),现在转为O类型(区域内),说明R3认为自已与192网段是直连的。虚链路相当于将R3直接连接了AREA 0 与 AREA 4区域
 
 
r4#sh ip ro
     4.0.0.0/24 is subnetted, 1 subnets
C       4.4.4.0 is directly connected, Loopback0
O IA 193.1.1.0/24 [110/20] via 194.1.1.3, 00:03:40, Ethernet0/0
O IA 192.1.1.0/24 [110/30] via 194.1.1.3, 00:03:25, Ethernet0/0
C    194.1.1.0/24 is directly connected, Ethernet0/0
//R4上192路由类型IA(区域间)
 
 
最后我们将虚链路效果再与正常连接方式进行一下比对,如下图:
OSPF虚链路(virtual-link)配置实例 + 详细验证过程



验证如下:
r1#sh ip ro
     1.0.0.0/24 is subnetted, 1 subnets
C       1.1.1.0 is directly connected, Loopback0
O IA 193.1.1.0/24 [110/20] via 192.1.1.2, 00:00:41, Ethernet0/0
C    192.1.1.0/24 is directly connected, Ethernet0/0
C    192.2.2.0/24 is directly connected, Ethernet1/0
O IA 194.1.1.0/24 [110/20] via 192.2.2.4, 00:00:39, Ethernet1/0
 
 
 
r2#sh ip ro
     2.0.0.0/24 is subnetted, 1 subnets
C       2.2.2.0 is directly connected, Loopback0
C    193.1.1.0/24 is directly connected, Ethernet1/0
C    192.1.1.0/24 is directly connected, Ethernet0/0
O    192.2.2.0/24 [110/20] via 192.1.1.1, 00:01:04, Ethernet0/0
O IA 194.1.1.0/24 [110/30] via 192.1.1.1, 00:00:03, Ethernet0/0
r2#
 
 
r3#sh ip ro
     3.0.0.0/24 is subnetted, 1 subnets
C       3.3.3.0 is directly connected, Loopback0
C    193.1.1.0/24 is directly connected, Ethernet1/0
O IA 192.1.1.0/24 [110/20] via 193.1.1.2, 00:01:31, Ethernet1/0
O IA 192.2.2.0/24 [110/30] via 193.1.1.2, 00:01:15, Ethernet1/0
O IA 194.1.1.0/24 [110/40] via 193.1.1.2, 00:00:15, Ethernet1/0
 
 
r4#sh ip ro
     4.0.0.0/24 is subnetted, 1 subnets
C       4.4.4.0 is directly connected, Loopback0
O IA 193.1.1.0/24 [110/30] via 192.2.2.1, 00:00:39, Ethernet1/0
O    192.1.1.0/24 [110/20] via 192.2.2.1, 00:01:37, Ethernet1/0
C    192.2.2.0/24 is directly connected, Ethernet1/0
C    194.1.1.0/24 is directly connected, Ethernet0/0
 
 
r5#sh ip ro
     5.0.0.0/24 is subnetted, 1 subnets
C       5.5.5.0 is directly connected, Loopback0
O IA 193.1.1.0/24 [110/40] via 194.1.1.4, 00:00:52, Ethernet0/0
O IA 192.1.1.0/24 [110/30] via 194.1.1.4, 00:00:52, Ethernet0/0
O IA 192.2.2.0/24 [110/20] via 194.1.1.4, 00:00:52, Ethernet0/0

C    194.1.1.0/24 is directly connected, Ethernet0/0
 
 
 
 
如果上述方式还不容易理解,你也可以将virtual-link可以想象成:将R2与R3合并成一台路由器,如下图:

OSPF虚链路(virtual-link)配置实例 + 详细验证过程


r1#sh ip ro
     1.0.0.0/24 is subnetted, 1 subnets
C       1.1.1.0 is directly connected, Loopback0
O IA 193.1.1.0/24 [110/20] via 192.1.1.2, 00:00:57, Ethernet0/0
C    192.1.1.0/24 is directly connected, Ethernet0/0
O IA 194.1.1.0/24 [110/74] via 192.1.1.2, 00:00:24, Ethernet0/0
 
 
r2#sh ip ro
     2.0.0.0/24 is subnetted, 1 subnets
C       2.2.2.0 is directly connected, Loopback0
C    193.1.1.0/24 is directly connected, Ethernet1/0
C    192.1.1.0/24 is directly connected, Ethernet0/0
C    194.1.1.0/24 is directly connected, Serial2/0
 
 
 
r3#sh ip ro
     3.0.0.0/24 is subnetted, 1 subnets
C       3.3.3.0 is directly connected, Loopback0
C    193.1.1.0/24 is directly connected, Ethernet1/0
O IA 192.1.1.0/24 [110/20] via 193.1.1.2, 00:01:06, Ethernet1/0
O IA 194.1.1.0/24 [110/74] via 193.1.1.2, 00:00:37, Ethernet1/0
 
 
r4#sh ip ro
     4.0.0.0/24 is subnetted, 1 subnets
C       4.4.4.0 is directly connected, Loopback0
O IA 193.1.1.0/24 [110/74] via 194.1.1.2, 00:00:17, Serial2/0
O IA 192.1.1.0/24 [110/74] via 194.1.1.2, 00:00:17, Serial2/0

C    194.1.1.0/24 is directly connected, Serial2/0
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