相信ospf大家都不会陌生,这是CCNP认证考试里经常出现的题目。ospf属于链路状态的路由协议,一般用于大型企业中,他是一个rfc标准不像eigrp是cisco的私有只能在cisco路由器上用,因此如果有不同厂商的路由器就要用ospf,当然我们还有强大的重分发工具可以使用。ospf有三张表,邻居表,可以通过命令show ip ospf nei查看。拓扑表,可以通过show ip ospf data查看,ospf根据拓扑表中的数据运行spf算法算出最佳路由放入第三张表,路由表,而这张表相信大家都不会陌生,而命令就更不用说了。 r1,r2和r3的e1/1,e1/2属于区域0.r3的e1/3,e1/4和r4,r5属于区域1.r1,r2,r4,r5都属于区域内路由器,r3属于abr。 下面是拓扑图,由5台思科路由器组网,灰常的简单,配置有点长。可能看着有点晕。 r1:
in e1/0 ip add 192.168.1.1 255.255.255.0 no sh in loop 1 ip add 172.16.0.1 255.255.255.0 in loop 2 ip add 172.16.1.1 255.255.255.0 in loop 3 ip add 172.16.2.1 255.255.255.0 in loop 4 ip add 172.16.3.1 255.255.255.0 router ospf 1 router-id 1.1.1.1 net 192.168.1.1 0.0.0.0 a 0 net 172.16.0.1 0.0.0.0 a 0 net 172.16.1.1 0.0.0.0 a 0 net 172.16.2.1 0.0.0.0 a 0 net 172.16.3.1 0.0.0.0 a 0 r2: in e1/1 ip add 192.168.2.1 255.255.255.0 no sh router ospf 1 net 192.168.2.1 0.0.0.0 a 0 router-d 2.2.2.2 r3: in e1/1 ip add 192.168.1.2 255.255.255.0 no sh in e1/2 ip add 192.168.2.2 255.255.255.0 no sh in e1/3 ip add 192.168.3.1 255.255.255.0 http://www.luyouqiwang.com/14476 no sh in e1/4 ip add 192.168.4.1 255.255.255.0 router ospf 1 router-id 3.3.3.3 net 192.168.1.2 0.0.0.0 a 0 net 192.168.2.2 0.0.0.0 a 0 net 192.168.3.1 0.0.0.0 a 1 net 192.168.4.1 0.0.0.0 a 1 r4: in e1/1 ip add 192.168.3.2 255.255.255.0 no sh in e1/2 ip add 192.168.5.2 255.255.255.0 no sh router ospf 1 router-id 4.4.4.4 net 192.168.3.2 0.0.0.0 a 1 net 192.168.5.2 0.0.0.0 a 1 r5: in e1/1 ip add 192.168.4.2 255.255.255.0 no sh in e1/2 ip add 192.168.5.1 255.255.255.0 no sh router ospf 1 net 192.168.4.2 0.0.0.0 a 1 net 192.168.5.1 0.0.0.0 a 1 验证命令:
show ip ro show ip ospf nei show runn 输出示例: 在R2上的路由表输出 R2#show ip ro 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 www.luyouqiwang.com/14476/ is subnetted, 4 subnets
O 172.16.1.1 [110/21] via 192.168.2.2, 00:00:03, Ethernet1/1 O 172.16.0.1 [110/21] via 192.168.2.2, 00:00:03, Ethernet1/1 O 172.16.3.1 [110/21] via 192.168.2.2, 00:00:03, Ethernet1/1 O 172.16.2.1 [110/21] via 192.168.2.2, 00:00:03, Ethernet1/1 O IA 192.168.4.0/24 [110/20] via 192.168.2.2, 00:00:03, Ethernet1/1 O IA 192.168.5.0/24 [110/30] via 192.168.2.2, 00:00:03, Ethernet1/1 O 192.168.1.0/24 [110/20] via 192.168.2.2, 00:00:03, Ethernet1/1 C 192.168.2.0/24 is directly connected, Ethernet1/1 O IA 192.168.3.0/24 [110/20] via 192.168.2.2, 00:00:03, Ethernet1/1 R2#show ip ospf nei Neighbor ID Pri State Dead Time Address Interface
3.3.3.3 1 FULL/BDR 00:00:39 192.168.2.2 Ethernet1/1 有一个很有趣的现象,从区域1学来的路由在O后面都有一个IA标志,这表明这是一条区域间路由。 再看看R5上的输出 R5#show ip ro 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, 4 subnets
O IA 172.16.1.1 [110/21] via 192.168.4.1, 00:18:29, Ethernet1/1 O IA 172.16.0.1 [110/21] via 192.168.4.1, 00:18:39, Ethernet1/1 O IA 172.16.3.1 [110/21] via 192.168.4.1, 00:18:19, Ethernet1/1 O IA 172.16.2.1 [110/21] via 192.168.4.1, 00:18:29, Ethernet1/1 C 192.168.4.0/24 is directly connected, Ethernet1/1 C 192.168.5.0/24 is directly connected, Ethernet1/3 O IA 192.168.1.0/24 [110/20] via 192.168.4.1, 00:36:11, Ethernet1/1 O IA 192.168.2.0/24 [110/20] via 192.168.4.1, 00:36:11, Ethernet1/1 O 192.168.3.0/24 [110/20] via 192.168.5.2, 00:36:11, Ethernet1/3 [110/20] via 192.168.4.1, 00:36:11, Ethernet1/1 R5#show ip ospf nei Neighbor ID Pri State Dead Time Address Interface
4.4.4.4 1 FULL/BDR 00:00:34 192.168.5.2 Ethernet1/3 3.3.3.3 1 FULL/DR 00:00:34 192.168.4.1 Ethernet1/1 是不是很简单? 上次我讲过eigrp汇总,这次顺便也讲一下ospf的汇总。ospf汇总只能在abr和asbr上汇总,而asbr我暂时不讲,今天先讲讲在abr上 的汇总。无论是从R5还是R2上的路由表输出都表明我配置的4个环回接口都被学习到了,而且有4条路由条目,我现在就进行汇总将这
4条路由汇总为1条。
r3:
router ospf 1 area 0 range 172.16.0.0 255.255.252.0 配置很简单,一条命令就搞定了,简单解释下area 0表示汇总区域0的路由,而后面的是具体的汇总路由。
再看看R5的输出 R5#show ip ro 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
172.16.0.0/22 is subnetted, 1 subnets
O IA 172.16.0.0 [110/21] via 192.168.4.1, 00:00:25, Ethernet1/1 C 192.168.4.0/24 is directly connected, Ethernet1/1 C 192.168.5.0/24 is directly connected, Ethernet1/3 O IA 192.168.1.0/24 [110/20] via 192.168.4.1, 00:42:10, Ethernet1/1 O IA 192.168.2.0/24 [110/20] via 192.168.4.1, 00:42:10, Ethernet1/1 O 192.168.3.0/24 [110/20] via 192.168.5.2, 00:42:10, Ethernet1/3 [110/20] via 192.168.4.1, 00:42:10, Ethernet1/1 r2上的路由输出 R2#show ip rout ospf 172.16.0.0/32 is subnetted, 4 subnets O 172.16.1.1 [110/21] via 192.168.2.2, 00:30:29, Ethernet1/1 O 172.16.0.1 [110/21] via 192.168.2.2, 00:30:29, Ethernet1/1 O 172.16.3.1 [110/21] via 192.168.2.2, 00:30:29, Ethernet1/1 O 172.16.2.1 [110/21] via 192.168.2.2, 00:30:29, Ethernet1/1 O IA 192.168.4.0/24 [110/20] via 192.168.2.2, 00:30:29, Ethernet1/1 O IA 192.168.5.0/24 [110/30] via 192.168.2.2, 00:30:29, Ethernet1/1 O 192.168.1.0/24 [110/20] via 192.168.2.2, 00:30:29, Ethernet1/1 O IA 192.168.3.0/24 [110/20] via 192.168.2.2, 00:30:29, Ethernet1/1 未汇总,我下去再看看。不管如何,OPSF协议的各种应用都是在ccnp考试里很经常出现的,大家需要多花时间来牢记和巩固才行。 |
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