OSPF虚链路（virtual-link）配置实例 + 详细验证过程-阿里云开发者社区

本文转自 ciscodocu51CTO博客，原文链接：http://blog.51cto.com/ciscodocu/52828

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：

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：

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

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

，如需转载请自行联系原作者

OSPF虚链路（virtual-link）配置实例 + 详细验证过程

热门文章

最新文章

相关电子书