一、实验目的：

1、掌握OSPF非绝对末节区域的配置。

二、  实验拓扑

 

三、实验步骤

1、按照拓扑图配置好各个路由器的接口IP、OSPF协议。配置好后在R3上用命令show ip route查看路由表。

R3#sh ip route

 

Gateway of last resort is not set

 

     172.16.0.0/16 is variably subnetted, 11 subnets, 2 masks

C       172.16.252.0/24 is directly connected, Loopback3

C       172.16.248.0/24 is directly connected, Loopback2

C       172.16.244.0/24 is directly connected, Loopback1

C       172.16.240.0/24 is directly connected, Loopback0

C       172.16.224.0/24 is directly connected, Serial1/1

O IA    172.16.1.0/24 [110/128] via 172.16.224.1, 00:03:14, Serial1/1

O IA    172.16.3.1/32 [110/65] via 172.16.224.1, 00:03:14, Serial1/1

O IA    172.16.112.1/32 [110/129] via 172.16.224.1, 00:03:14, Serial1/1

O IA    172.16.96.1/32 [110/129] via 172.16.224.1, 00:03:14, Serial1/1

O IA    172.16.80.1/32 [110/129] via 172.16.224.1, 00:03:14, Serial1/1

O IA    172.16.64.1/32 [110/129] via 172.16.224.1, 00:03:14, Serial1/1

在R3将直连网络重分布到OSPF中，配置如下

R3(config)#router ospf 1

R3(config-router)#redistribute connected subnets

查看R1的路由表，将R3的物理直连网络学习到了如下：

R1#sh ip route

 

Gateway of last resort is not set

 

     172.16.0.0/16 is variably subnetted, 7 subnets, 2 masks

O IA    172.16.224.0/24 [110/128] via 172.16.1.2, 00:02:43, Serial1/1

C       172.16.1.0/24 is directly connected, Serial1/1

O       172.16.3.1/32 [110/65] via 172.16.1.2, 00:02:43, Serial1/1

C       172.16.112.0/24 is directly connected, Loopback3

C       172.16.96.0/24 is directly connected, Loopback2

C       172.16.80.0/24 is directly connected, Loopback1

C       172.16.64.0/24 is directly connected, Loopback0

     10.0.0.0/24 is subnetted, 1 subnets

C       10.0.0.0 is directly connected, Loopback5

查看R3的路由表

R3#sh ip route

 

Gateway of last resort is not set

 

     172.16.0.0/16 is variably subnetted, 11 subnets, 2 masks

C       172.16.252.0/24 is directly connected, Loopback3

C       172.16.248.0/24 is directly connected, Loopback2

C       172.16.244.0/24 is directly connected, Loopback1

C       172.16.240.0/24 is directly connected, Loopback0

C       172.16.224.0/24 is directly connected, Serial1/1

O IA    172.16.1.0/24 [110/128] via 172.16.224.1, 00:00:41, Serial1/1

O IA    172.16.3.1/32 [110/65] via 172.16.224.1, 00:00:41, Serial1/1

O IA    172.16.112.1/32 [110/129] via 172.16.224.1, 00:00:41, Serial1/1

O IA    172.16.96.1/32 [110/129] via 172.16.224.1, 00:00:41, Serial1/1

O IA    172.16.80.1/32 [110/129] via 172.16.224.1, 00:00:41, Serial1/1

O IA    172.16.64.1/32 [110/129] via 172.16.224.1, 00:00:41, Serial1/1

已经将R3的物理直连网络加入到了area 51中去。

2、在R3使用show ip ospf database查看LSA链路状态信息，

R3#sh ip ospf database

 

            OSPF Router with ID (172.16.252.1) (Process ID 1)

 

                Router Link States (Area 51)

 

Link ID         ADV Router      Age         Seq#       Checksum Link count

172.16.3.1      172.16.3.1      358         0x80000002 0x003BEE 2

172.16.252.1    172.16.252.1    115         0x80000002 0x00EE3F 2

 

                Summary Net Link States (Area 51)

 

Link ID         ADV Router      Age         Seq#       Checksum

172.16.1.0      172.16.3.1      385         0x80000001 0x00CDB0

172.16.3.1      172.16.3.1      385         0x80000001 0x003585

172.16.64.1     172.16.3.1      385         0x80000001 0x001627

172.16.80.1     172.16.3.1      385         0x80000001 0x0065C7

172.16.96.1     172.16.3.1      385         0x80000001 0x00B468

172.16.112.1    172.16.3.1      385         0x80000001 0x000409

 

                Type-5 AS External Link States

 

Link ID         ADV Router      Age         Seq#       Checksum Tag

172.16.240.0    172.16.252.1    115         0x80000001 0x0084B3 0

172.16.244.0    172.16.252.1    115         0x80000001 0x0058DB 0

172.16.248.0    172.16.252.1    115         0x80000001 0x002C04 0

172.16.252.0    172.16.252.1    115         0x80000001 0x00FF2C 0

可以看到出现Type-5链路状态信息，现在将area 51配置成非绝对末节区域。

R2(config)#router ospf 1

R2(config-router)#area 51 nssa

R2(config-router)#

 

R3(config)#router ospf 1

R3(config-router)#area 51 nssa

R3(config-router)#

*Nov 18 00:02:52.959: %OSPF-5-ADJCHG: Process 1, Nbr 172.16.3.1 on Serial1/1 from FULL to DOWN, Neighbor Down: Adjacency forced to reset

*Nov 18 00:03:12.595: %OSPF-5-ADJCHG: Process 1, Nbr 172.16.3.1 on Serial1/1 from LOADING to FULL, Loading Done

再次在R3使用show ip ospf database查看LSA链路状态信息

R3#sh ip ospf data

 

            OSPF Router with ID (172.16.252.1) (Process ID 1)

 

                Router Link States (Area 51)

 

Link ID         ADV Router      Age         Seq#       Checksum Link count

172.16.3.1      172.16.3.1      12          0x80000004 0x00E23D 2

172.16.252.1    172.16.252.1    16          0x80000004 0x009095 2

 

                Summary Net Link States (Area 51)

 

Link ID         ADV Router      Age         Seq#       Checksum

172.16.1.0      172.16.3.1      18          0x80000002 0x007106

172.16.3.1      172.16.3.1      18          0x80000002 0x00D8DA

172.16.64.1     172.16.3.1      18          0x80000002 0x00B97C

172.16.80.1     172.16.3.1      18          0x80000002 0x00091D

172.16.96.1     172.16.3.1      18          0x80000002 0x0058BD

172.16.112.1    172.16.3.1      18          0x80000002 0x00A75E

 

                Type-7 AS External Link States (Area 51)

 

Link ID         ADV Router      Age         Seq#       Checksum Tag

172.16.240.0    172.16.252.1    35          0x80000001 0x00A3EA 0

172.16.244.0    172.16.252.1    35          0x80000001 0x007713 0

172.16.248.0    172.16.252.1    36          0x80000001 0x004B3B 0

172.16.252.0    172.16.252.1    36          0x80000001 0x001F63 0

R3#

可以看到在R3的拓扑数据库里还有汇总的链路LSA，但Type-5链路状态信息已经没有了，转变成了Type-7的链路状态信息，也就是说还可以让type3,type4的LAS扩散到非绝对末节区域中。配置R2来禁止汇总链路LSA扩散到非绝对末节区域中, 配置如下:

R2(config)#router ospf 1

R2(config-router)#area 51 nssa no-summary

配置完后查看R的路由表，内部区域路由被一条默认路由所代替：

R3#sh ip route

 

Gateway of last resort is 172.16.224.1 to network 0.0.0.0

 

     172.16.0.0/24 is subnetted, 5 subnets

C       172.16.252.0 is directly connected, Loopback3

C       172.16.248.0 is directly connected, Loopback2

C       172.16.244.0 is directly connected, Loopback1

C       172.16.240.0 is directly connected, Loopback0

C       172.16.224.0 is directly connected, Serial1/1

O*IA 0.0.0.0/0 [110/65] via 172.16.224.1, 00:00:22, Serial1/1

在R2上使用show ip ospf database查看拓扑数据库的信息，发现有TYPE5和TYPE7的链路状态LSA.

R2#sh ip ospf database

 

            OSPF Router with ID (172.16.3.1) (Process ID 1)

 

                Router Link States (Area 0)

 

Link ID         ADV Router      Age         Seq#       Checksum Link count

172.16.3.1      172.16.3.1      192         0x80000004 0x009C03 3

172.16.112.1    172.16.112.1    721         0x80000003 0x000206 2

 

                Summary Net Link States (Area 0)

 

Link ID         ADV Router      Age         Seq#       Checksum

172.16.64.1     172.16.112.1    823         0x80000001 0x00957A

172.16.80.1     172.16.112.1    788         0x80000001 0x00E41B

172.16.96.1     172.16.112.1    778         0x80000001 0x0034BB

172.16.112.1    172.16.112.1    758         0x80000001 0x00835C

172.16.224.0    172.16.3.1      667         0x80000001 0x002F6F

 

                Router Link States (Area 51)

 

Link ID         ADV Router      Age         Seq#       Checksum Link count

172.16.3.1      172.16.3.1      187         0x80000004 0x00E23D 2

172.16.252.1    172.16.252.1    192         0x80000004 0x009095 2

         

                Summary Net Link States (Area 51)

 

Link ID         ADV Router      Age         Seq#       Checksum

0.0.0.0         172.16.3.1      58          0x80000001 0x008BE9

 

                Type-7 AS External Link States (Area 51)

 

Link ID         ADV Router      Age         Seq#       Checksum Tag

172.16.240.0    172.16.252.1    212         0x80000001 0x00A3EA 0

172.16.244.0    172.16.252.1    212         0x80000001 0x007713 0

172.16.248.0    172.16.252.1    212         0x80000001 0x004B3B 0

172.16.252.0    172.16.252.1    212         0x80000001 0x001F63 0

 

                Type-5 AS External Link States

 

Link ID         ADV Router      Age         Seq#       Checksum Tag

172.16.240.0    172.16.3.1      172         0x80000001 0x000E84 0

172.16.244.0    172.16.3.1      172         0x80000001 0x00E1AC 0

172.16.248.0    172.16.3.1      172         0x80000001 0x00B5D4 0

172.16.252.0    172.16.3.1      172         0x80000001 0x0089FC 0

使用show ip route 查看R2的路由表:

R2#sh ip route

 

Gateway of last resort is not set

 

     172.16.0.0/16 is variably subnetted, 11 subnets, 2 masks

O N2    172.16.252.0/24 [110/20] via 172.16.224.2, 00:01:44, Serial1/2

O N2    172.16.248.0/24 [110/20] via 172.16.224.2, 00:01:44, Serial1/2

O N2    172.16.244.0/24 [110/20] via 172.16.224.2, 00:01:44, Serial1/2

O N2    172.16.240.0/24 [110/20] via 172.16.224.2, 00:01:44, Serial1/2

C       172.16.224.0/24 is directly connected, Serial1/2

C       172.16.1.0/24 is directly connected, Serial1/0

C       172.16.3.0/24 is directly connected, Loopback0

O IA    172.16.112.1/32 [110/65] via 172.16.1.1, 00:01:44, Serial1/0

O IA    172.16.96.1/32 [110/65] via 172.16.1.1, 00:01:44, Serial1/0

O IA    172.16.80.1/32 [110/65] via 172.16.1.1, 00:01:44, Serial1/0

O IA    172.16.64.1/32 [110/65] via 172.16.1.1, 00:01:44, Serial1/0

同样，使用show ip route 查看R1的路由表

R1#  sh ip route

 

Gateway of last resort is not set

 

     172.16.0.0/16 is variably subnetted, 11 subnets, 2 masks

O E2    172.16.252.0/24 [110/20] via 172.16.1.2, 00:03:53, Serial1/1

O E2    172.16.248.0/24 [110/20] via 172.16.1.2, 00:03:53, Serial1/1

O E2    172.16.244.0/24 [110/20] via 172.16.1.2, 00:03:53, Serial1/1

O E2    172.16.240.0/24 [110/20] via 172.16.1.2, 00:03:53, Serial1/1

O IA    172.16.224.0/24 [110/128] via 172.16.1.2, 00:04:09, Serial1/1

C       172.16.1.0/24 is directly connected, Serial1/1

O       172.16.3.1/32 [110/65] via 172.16.1.2, 00:04:09, Serial1/1

C       172.16.112.0/24 is directly connected, Loopback3

C       172.16.96.0/24 is directly connected, Loopback2

C       172.16.80.0/24 is directly connected, Loopback1

C       172.16.64.0/24 is directly connected, Loopback0

     10.0.0.0/24 is subnetted, 1 subnets

可以看到R2将N2(TYPE7)的LSA，转换成E2(TYPE5)的LSA扩散到区域1里面。

 

本文转自 独钩寒江雪 51CTO博客，原文链接：http://blog.51cto.com/bennie/428081，如需转载请自行联系原作者