OSPFv2是OSPF第２个版本，与RIP相比它收敛速度快，适用于规模较大的网络。
OSPFv2使用了区域的概念，可以把路由器划分为不同的区域然后进行流量的控制 。
和OSPF相比，增加router-id的ospf就是ospf v2
1.R1(config-router)#auto-cost reference-bandwidth 1000
[修改参考带宽为1000Mbps] 这两条命令是干预OSPFv2自动选路的
2.R1(config-if)#ip ospf cost 3 [修改接口开销为3]
就像这样，默认路径走的是中间的百兆路线，如果想让他默认走两侧的前兆 路线，就需要更改他的参考带宽
比如改成1000mbps，就可以默认走两侧的千兆路线走
验证PC1与PC2互通时流量经过的路径
C:\>tracert 192.168.2.1
Tracing route to 192.168.2.1 over a maximum of 30 hops:
1 0 ms 0 ms 0 ms 192.168.1.254 //路由器R1
2 0 ms 0 ms 0 ms 10.2.13.3 //路由器R3
3 0 ms 0 ms 0 ms 10.2.36.6 //路由器R6
4 0 ms 0 ms 10 ms 10.2.68.8 //路由器R8
5 0 ms 11 ms 0 ms 192.168.2.1 //目的主机
Trace complete.
3.R1(config-if)#ip ospf hello-interval 5
R1(config-if)#ip ospf dead-interval 20
[接口的Hello间隔和Dead间隔默认值为10s和40s]
[这两条是修改路由器Hello间隔、Dead间隔干预邻接关系的，若两端间隔设置不相同，会导致邻里关系失效]
修改OSPF v2协议中：hello和dead间隔后，会发现两端路由器建立邻接关系
所以两端的hello和dead必须相同，如果不同的话会造成邻接关系失效
所以要么还原这台路由器的设置，或者将另一台路由器也修改成相同的参数即可恢复
R2(config)#in g 0/0
R2(config-if)#
R2(config-if)#ip os
R2(config-if)#ip ospf h
R2(config-if)#ip ospf hello-interval 5
R2(config-if)#ip o
R2(config-if)#ip ospf de
R2(config-if)#ip ospf dead-interval 20
R2(config-if)#do sh ip os ne
Neighbor ID Pri State Dead Time Address Interface
1.1.1.1 1 FULL/DR 00:00:29 10.0.12.1 GigabitEthernet0/0
R2(config-if)#do sh ip os ne
Neighbor ID Pri State Dead Time Address Interface
1.1.1.1 1 FULL/DR 00:00:09 10.0.12.1 GigabitEthernet0/0
R2(config-if)#do sh ip os ne
Neighbor ID Pri State Dead Time Address Interface
1.1.1.1 1 FULL/DR 00:00:08 10.0.12.1 GigabitEthernet0/0
R2(config-if)#do sh ip os ne
Neighbor ID Pri State Dead Time Address Interface
1.1.1.1 1 FULL/DR 00:00:00 10.0.12.1 GigabitEthernet0/0
R2(config-if)#
00:08:37: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on GigabitEthernet0/0 from FULL to DOWN, Neighbor Down: Dead timer expired
00:08:37: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on GigabitEthernet0/0 from FULL to DOWN, Neighbor Down: Interface down or detached
修改成默认设置之后会发现他们之间邻里关系恢复正常了
R2(config-if)#ip ospf he
R2(config-if)#ip ospf hello-interval 10
R2(config-if)#ip os de
R2(config-if)#ip os dead-interval 40
R2(config-if)#do sh ip os ne
Neighbor ID Pri State Dead Time Address Interface
1.1.1.1 1 INIT/DROTHER 00:00:36 10.0.12.1 GigabitEthernet0/0
R2(config-if)#
00:15:33: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on GigabitEthernet0/0 from LOADING to FULL, Loading Done
4.R2(config-if)#ip ospf priority 0[修改OSPF接口优先级为0]
5..R2#clear ip ospf process [重置OSPFv2进程]
修改OSPFV2接口优先级，重置一下OSPFV2进程之后就可以重新建立邻接关系
R2(config-if)#ip ospf priority 0
R2(config-if)#do clear ip ospf pro
Reset ALL OSPF processes? [no]: y
R2(config-if)#
00:18:22: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on GigabitEthernet0/0 from FULL to DOWN, Neighbor Down: Adjacency forced to reset
00:18:22: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on GigabitEthernet0/0 from FULL to DOWN, Neighbor Down: Interface down or detached
R2(config-if)#
00:18:24: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on GigabitEthernet0/0 from LOADING to FULL, Loading Done
当两台路由器接口优先级都设置为0时，接口状态会显示2WAY，这个时候网络中就不存在DR/BDR信息，所以R1R2这个时候都会变成DROTHER，这种状态下是一个错误的状态，这样会使邻接关系发生错误，进而无法形成路由表
想要改变这种故障，只需要修改一台路由器的优先级非0即可，也可以修改为点到点类型{point-to-point}
R1#show ip os neighbor
Neighbor ID Pri State Dead Time Address Interface
2.2.2.2 0 2WAY/DROTHER 00:00:39 10.0.12.2 GigabitEthernet0/0
R1#
R1#ping 10.2.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.2.1.2, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)6.R1(config-if)#ip ospf network point-to-point [修改OSPFV2接口模式为点到点类型]
修改两边路由器接口类型为点对点模式，即可排除故障
R2(config)#in g 0/0
R2(config-if)#ip os net point-to-point
R2(config-if)#
00:35:03: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on GigabitEthernet0/0 from 2WAY to DOWN, Neighbor Down: Interface down or detached
00:35:03: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on GigabitEthernet0/0 from LOADING to FULL, Loading Done
R2(config-if)#do sh ip os ne
Neighbor ID Pri State Dead Time Address Interface
1.1.1.1 0 FULL/ - 00:00:35 10.0.12.1 GigabitEthernet0/0
R2#
%SYS-5-CONFIG_I: Configured from console by console
两侧修改之后可以发现，两侧正常通信了
R2#ping 10.2.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.2.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 0/2/5 ms
R2#