重发布实验
1.规划接口IP地址和本地环回地址
[r1]interface LoopBack 0
[r1-LoopBack0]ip address 1.1.1.1 24
[r1-LoopBack0]int g0/0/0
[r1-GigabitEthernet0/0/0]ip address 12.1.1.1 24
[r2]interface LoopBack 0
[r2-LoopBack0]ip address 2.2.2.2 24
[r2-LoopBack0]int g0/0/0
[r2-GigabitEthernet0/0/0]ip address 12.1.1.2 24
[r2-GigabitEthernet0/0/0]int g0/0/1
[r2-GigabitEthernet0/0/1]ip address 23.1.1.1 24
[r3]int LoopBack 0
[r3-LoopBack0]ip address 3.3.3.3 24
[r3-LoopBack0]int g0/0/0
[r3-GigabitEthernet0/0/0]ip address 23.1.1.2 24
[r3-GigabitEthernet0/0/0]int g0/0/1
[r3-GigabitEthernet0/0/1]ip address 34.1.1.1 24
[r3-GigabitEthernet0/0/1]int g0/0/2
[r3-GigabitEthernet0/0/2]ip address 36.1.1.1 24
[r4]interface LoopBack 0
[r4-LoopBack0]ip address 4.4.4.4 24
[r4-LoopBack0]int g0/0/0
[r4-GigabitEthernet0/0/0]ip address 34.1.1.2 24
[r4-GigabitEthernet0/0/0]int g0/0/1
[r4-GigabitEthernet0/0/1]ip address 45.1.1.1 24
[r5]interface LoopBack 0
[r5-LoopBack0]ip address 5.5.5.5 24
[r5-LoopBack0]int g0/0/0
[r5-GigabitEthernet0/0/0]ip address 45.1.1.2 24
[r5-GigabitEthernet0/0/0]int g0/0/1
[r5-GigabitEthernet0/0/1]ip address 56.1.1.1 24
[r6]int LoopBack 0
[r6-LoopBack0]ip address 6.6.6.6 24
[r6-LoopBack0]int g0/0/0
[r6-GigabitEthernet0/0/0]ip address 56.1.1.2 24
[r6-GigabitEthernet0/0/0]int g0/0/1
[r6-GigabitEthernet0/0/1]ip address 36.1.1.2 24
2.R1-R2-R3-R4-R6之间使用OSPF协议，R4-R5-R6之间使用RIP协议
[r1]ospf 100 router-id 91.1.1.1
[r1-ospf-100]area 0
[r1-ospf-100-area-0.0.0.0]network 12.1.1.1 0.0.0.0
[r2]ospf 100 router-id 92.2.2.2
[r2-ospf-100]area 0
[r2-ospf-100-area-0.0.0.0]network 12.1.1.2 0.0.0.0
[r2-ospf-100-area-0.0.0.0]network 23.1.1.1 0.0.0.0
[r2-ospf-100-area-0.0.0.0]network 2.2.2.2 0.0.0.0
[r3]ospf 100 router-id 93.3.3.3
[r3-ospf-100]area 0
[r3-ospf-100-area-0.0.0.0]network 23.1.1.2 0.0.0.0
[r3-ospf-100-area-0.0.0.0]network 34.1.1.1 0.0.0.0
[r3-ospf-100-area-0.0.0.0]network 36.1.1.1 0.0.0.0
[r3-ospf-100-area-0.0.0.0]network 3.3.3.3 0.0.0.0
[r4]ospf 100 router-id 94.4.4.4
[r4-ospf-100]area 0
[r4-ospf-100-area-0.0.0.0]network 34.1.1.2 0.0.0.0
[r4-ospf-100-area-0.0.0.0]network 4.4.4.4 0.0.0.0
[r6]ospf 100 router-id 96.6.6.6
[r6-ospf-100]area 0
[r6-ospf-100-area-0.0.0.0]network 36.1.1.2 0.0.0.0
[r6-ospf-100-area-0.0.0.0]network 6.6.6.6 0.0.0.0
[r4-ospf-100-area-0.0.0.0]rip 100
[r4-rip-100]version 2
[r4-rip-100]network 45.0.0.0
[r5]rip 100
[r5-rip-100]version 2
[r5-rip-100]network 5.0.0.0
[r5-rip-100]network 56.0.0.0
[r5-rip-100]network 45.0.0.0
[r6]rip 100
[r6-rip-100]version 2
[r6-rip-100]network 56.0.0.0
3.R1环回重发布方式引入OSPF网络
[r1]ospf 100 router-id 91.1.1.1
[r1-ospf-100]import-route direct
4.R4/R6上进行双点双向重发布
[r4-rip-100]import-route ospf 100
[r4-rip-100]ospf 100
[r4-ospf-100]import-route rip 100
[r6-rip-100]import-route ospf 100
[r6-rip-100]ospf 100
[r6-ospf-100]import-route rip 100
5.查看r3 r4 r5 r6的路由表
在这里插入图片描述
观察路由表，发现r3通过r4访问r1的环回，r4通过r5访问r1的环回，r5通过r6访问r1的环回，r6通过r3访问r1的环回。这就形成了一个环路，形成的原因是：RIP路由的优先级为100，而OSPF内部路由优先级是10，外部路由优先级是150，OSPF域外路1.1.1.0/24，这条路由是R1重分发到OSPF的，R4能够通过OSPF学习到该条路由并将其加载进路由表。另一方面，R4又会从RIP学习到1.1.1.0/24路由，这就出问题了，因为RIP路由的优先级要高于OSPF外部路由，因此最终到1.1.1.0/24，R3会优选RIP路由，这样环路问题也就出现了。
我们可以通过调整路由优先级的方法解决该问题，在R4以及R6上把1.1.1.0/24这条OSPF域外路由的优先级调的比RIP路由的优先级更低：
[r4]acl 2000
[r4-acl-basic-2000]rule permit source 1.1.1.0 0.0.0.0
[r4-acl-basic-2000]q
[r4]route-policy hcip permit node 10
Info: New Sequence of this List.
[r4-route-policy]if-match acl 2000
[r4-route-policy]apply preference 99
[r4-route-policy]q
[r4]ospf 100
[r4-ospf-100]preference ase route-policy hcip
[r6]acl 2000
[r6-acl-basic-2000]rule permit source 1.1.1.0 0.0.0.0
[r6-acl-basic-2000]q
[r6]route-policy hcip permit node 10
Info: New Sequence of this List.
[r6-route-policy]if-match acl 2000
[r6-route-policy]apply preference 99
[r6-route-policy]q
[r6]ospf 100
[r6-ospf-100]preference route-policy hcip
查看r5 r4 路由表测试