一、思路 ； 

1.增加不优选路开销解决选路不佳问题

2.用增加开销的方式使R1 不将ASBR传的R7传给另一台ASBR解决R1、R2、R3、R4pingR7环回环路

二、操作

------IP地址配置如图

1.解决环路

[r2] ip ip-prefix a  permit  7.7.7.0 24

[r2]route-policy huawei permit node 10
[r2-route-policy]if-match ip-prefix a
[r2-route-policy]apply cost 14
[r2-route-policy]q

[r3] ip ip-prefix a  permit  7.7.7.0 24

[r3]route-policy huawei permit node 10
[r3-route-policy]if-match ip-prefix a
[r3-route-policy]apply cost 14
[r3-route-policy]q

[r2]ospf 1
[r2-ospf-1]import-route rip 1 route-policy hua 

[r3]ospf 1
[r3-ospf-1]import-route rip 1 route-policy hua 

2.解决选路不佳

R1

[r1]ip ip-prefix aa permit 24.1.1.0 24
[r1]ip ip-prefix bb permit 34.1.1.0 24
[r1]ip ip-prefix bb permit 3.3.3.3 32
[r1]int g0/0/0 
[r1-GigabitEthernet0/0/0]rip metricin ip-prefix aa 2
[r1-GigabitEthernet0/0/0]int g0/0/1                 
[r1-GigabitEthernet0/0/1]rip metricin ip-prefix bb 2
[r1-GigabitEthernet0/0/1]

R4

[r3] ip ip-prefix b  permit 12.1.1.0 24 

[r3] ip ip-prefix b  permit 2.2.2.024 

[r2] ip ip-prefix b  permit 13.1.1.0 24

[r2]route-policy hua permit node 10
[r2-route-policy]if-match ip-prefix b
[r2-route-policy]apply cost 7

[r2-route-policy]q

[r2]route-policy huawei permit node 30

[r3]route-policy huawei permit node 30

[r3]route-policy hua permit node 10
[r3-route-policy]if-match ip-prefix b
[r3-route-policy]apply cost 7

[r3-route-policy]q

[r3]route-policy huawei permit node 30

[r2]rip 1                                 
[r2-rip-1]import-route ospf 1 route-policy huawei

[r3]rip 1                                 
[r3-rip-1]import-route ospf 1 route-policy huawei

三、检验查看R1、R4路由表