将ospf与rip相互引入。由于华为的ospf内部路由优先级为10，外部引入路由优先级为150 。RIP的优先级为100。所以RIP的路由优先级比ospf的外部引入的小，故RIP路由优先于ospf外部路由。
刚构建的拓扑，并不存在环路和次优路径，当ar2上的接口出现down的现象后，才会出现次优路径或者环路现象
disp ip routing-table
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Tables: Public
Destinations : 18 Routes : 18
Destination/Mask Proto Pre Cost Flags NextHop Interface
10.1.12.0/24 OSPF 10 2 D 10.1.24.2 GigabitEthernet0/0/0
10.1.23.0/24 OSPF 10 2 D 10.1.24.2 GigabitEthernet0/0/0
10.1.24.0/24 Direct 0 0 D 10.1.24.4 GigabitEthernet0/0/0
10.1.24.4/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0
10.1.24.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0
22.1.1.1/32 OSPF 10 1 D 10.1.24.2 GigabitEthernet0/0/0
33.1.1.1/32 OSPF 10 2 D 10.1.24.2 GigabitEthernet0/0/0
44.1.1.1/32 Direct 0 0 D 127.0.0.1 LoopBack0
127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0
127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0
127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
172.16.0.0/24 O_ASE 150 1 D 10.1.24.2 GigabitEthernet0/0/0 172.16.2.0/24 O_ASE 150 1 D 10.1.24.2 GigabitEthernet0/0/0
192.168.35.0/24 O_ASE 150 1 D 10.1.24.2 GigabitEthernet0/0/0
192.168.45.0/24 Direct 0 0 D 192.168.45.4 GigabitEthernet0/0/1
192.168.45.4/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1
192.168.45.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1
255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
[ar3]disp ip routing-table
Route Flags: R - relay, D - download to fib
------------------------------------------------------------------------------
Routing Tables: Public
Destinations : 18 Routes : 18
Destination/Mask Proto Pre Cost Flags NextHop Interface
10.1.12.0/24 OSPF 10 2 D 10.1.23.2 GigabitEthernet0/0/0
10.1.23.0/24 Direct 0 0 D 10.1.23.3 GigabitEthernet0/0/0
10.1.23.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0
10.1.23.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/0
10.1.24.0/24 OSPF 10 2 D 10.1.23.2 GigabitEthernet0/0/0
22.1.1.1/32 OSPF 10 1 D 10.1.23.2 GigabitEthernet0/0/0
33.1.1.1/32 Direct 0 0 D 127.0.0.1 LoopBack0
44.1.1.1/32 OSPF 10 2 D 10.1.23.2 GigabitEthernet0/0/0
127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0
127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0
127.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
172.16.0.0/24 O_ASE 150 1 D 10.1.23.2 GigabitEthernet0/0/0
172.16.2.0/24 O_ASE 150 1 D 10.1.23.2 GigabitEthernet0/0/0
192.168.35.0/24 Direct 0 0 D 192.168.35.3 GigabitEthernet0/0/1
192.168.35.3/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1
192.168.35.255/32 Direct 0 0 D 127.0.0.1 GigabitEthernet0/0/1
192.168.45.0/24 O_ASE 150 1 D 10.1.23.2 GigabitEthernet0/0/0
255.255.255.255/32 Direct 0 0 D 127.0.0.1 InLoopBack0
当ar3与ar2的邻居状态出现震荡后
ar3收到172.16.0.0/24和172.16.2.0/24的路由会由于ospf的震荡导致邻居关系重新建立，LSA重新交互。同时由于RIP并没有断开，同时因为rip的路由优先级比ospf的外部路由要低，所以ar3的172.16.0.0/24和172.16.2.0/24两个路由浮现的协议为RIP。导致次优路径的产生。
Ar4因为没有产生震荡所以路由表没有改变。Ar4和ar2之间链路状态出现变化同样道理。
