多区域ospf的基本配置
好久没有做过实验了，今天按照按照工大瑞普的实验手册来做ospf的的实验。
拓扑图如图所示
实验目的：
1、掌握多区域的OSPF配置方法。
2、区别不同区域的路由。
3、掌握OSPF的路由汇总配置。
4、掌握OSPF的基本配置命令
废话不说，首先按照拓扑图上的要求将路由器的直连接口配置ip地址，配置的时候要注意注意子网掩码与其反掩码，配置完ip地址后，使用ping 命令测试，直连网段是否能够ping通。
然后开始配置ospf。
R1配置如下
router ospf 1
network 10.1.1.0 0.0.0.255 area 1
network 10.1.2.0 0.0.0.255 area 1
network 192.168.1.0 0.0.0.3 area 1
R2配置如下
router ospf 1
lnetwork 192.168.1.0 0.0.0.3 area 1
network 192.168.1.4 0.0.0.3 area 0
R3 配置如下
router ospf 1
network 192.168.1.4 0.0.0.3 area 0
network 192.168.1.8 0.0.0.3 area 2
R4配置如下
router ospf 1
network 172.16.1.0 0.0.0.255 area 2
network 172.16.2.0 0.0.0.255 area 2
network 192.168.1.8 0.0.0.3 area 2 （注意反掩码）
ospf的基本配置就配置完成了，可以用ping命令 ，在R1上 ping 172.16.1.1
输出：Router#ping 172.16.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.1.1, timeout is 2 seconds:
!!!!!
在R2上查看ospf的邻居表
Router#show ip ospf nei
Neighbor ID Pri State Dead Time Address Interface
192.168.1.9 0 FULL/ - 00:00:34 192.168.1.6 Serial2/1
10.1.2.1 0 FULL/ - 00:00:29 192.168.1.1 Serial2/0
以上说明 R2已经与另外两台路由器建立了邻居关系。
在R1上查看路由表
Router#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O -
OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
172.16.0.0/32 is subnetted, 2 subnets
O IA 172.16.1.1 [110/193] via 192.168.1.2, 00:11:28, Serial2/0 （IA表示从其他区域学习到的路由）
O IA 172.16.2.1 [110/193] via 192.168.1.2, 00:11:25, Serial2/0
10.0.0.0/24 is subnetted, 2 subnets
C 10.1.2.0 is directly connected, Loopback1
C 10.1.1.0 is directly connected, Loopback0
192.168.1.0/30 is subnetted, 3 subnets
O IA 192.168.1.8 [110/192] via 192.168.1.2, 00:12:02, Serial2/0
C 192.168.1.0 is directly connected, Serial2/0
O IA 192.168.1.4 [110/128] via 192.168.1.2, 00:13:32, Serial2/0
查看R4的路由表和R4的链路状态数据库
Router#show ip ospf dat
OSPF Router with ID (172.16.2.1) (Process ID 1)
Router Link States (Area 2)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.1 172.16.2.1 1428 0x80000004 0x00B871 4
192.168.1.9 192.168.1.9 1456 0x80000002 0x00EA2E 2
Summary Net Link States (Area 2)
Link ID ADV Router Age Seq# Checksum
10.1.1.1 192.168.1.9 1040 0x80000001 0x00AB8F
10.1.2.1 192.168.1.9 1040 0x80000001 0x00A099
192.168.1.0 192.168.1.9 1482 0x80000001 0x00766B
192.168.1.4 192.168.1.9 1497 0x80000001 0x00CB52
Router#
Router#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O -
OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
172.16.0.0/24 is subnetted, 2 subnets
C 172.16.1.0 is directly connected, Loopback0
C 172.16.2.0 is directly connected, Loopback1
10.0.0.0/32 is subnetted, 2 subnets
O IA 10.1.2.1 [110/193] via 192.168.1.9, 00:17:33, Serial2/0
O IA 10.1.1.1 [110/193] via 192.168.1.9, 00:17:33, Serial2/0
192.168.1.0/30 is subnetted, 3 subnets
C 192.168.1.8 is directly connected, Serial2/0
O IA 192.168.1.0 [110/192] via 192.168.1.9, 00:23:59, Serial2/0
O IA 192.168.1.4 [110/128] via 192.168.1.9, 00:23:59, Serial2/0
可以发现R4路由器学习到area1区域的具体路由，其实，可以通过在R2(ABR)上可以对area1的路由进行汇总，通过汇总可以有效的减少路由表的大小，限制LSA扩散。
在R2上进行配置
Router(config)router ospf 1
Router(config-router)#area 1 range 10.1.0.0 255.255.0.0
然后继续在R4上查看路由表和链路状态数据库。
Router#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O -
OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
172.16.0.0/24 is subnetted, 2 subnets
C 172.16.1.0 is directly connected, Loopback0
C 172.16.2.0 is directly connected, Loopback1
10.0.0.0/16 is subnetted, 1 subnets
O IA 10.1.0.0 [110/193] via 192.168.1.9, 00:00:02, Serial2/0
192.168.1.0/30 is subnetted, 3 subnets
C 192.168.1.8 is directly connected, Serial2/0
O IA 192.168.1.0 [110/192] via 192.168.1.9, 00:24:56, Serial2/0
O IA 192.168.1.4 [110/128] via 192.168.1.9, 00:24:56, Serial2/0
Router#show ip ospf dat
OSPF Router with ID (172.16.2.1) (Process ID 1)
Router Link States (Area 2)
Link ID ADV Router Age Seq# Checksum Link count
172.16.2.1 172.16.2.1 1574 0x80000004 0x00B871 4
192.168.1.9 192.168.1.9 1602 0x80000002 0x00EA2E 2
Summary Net Link States (Area 2)
Link ID ADV Router Age Seq# Checksum
10.1.0.0 192.168.1.9 80 0x80000001 0x00C07C
192.168.1.0 192.168.1.9 1628 0x80000001 0x00766B
192.168.1.4 192.168.1.9 1643 0x80000001 0x00CB52
我们会发现进行汇总后，R2配置以后，R4学习到的路由表要比在没有汇总以前要小，限制了lsa的扩散。