日前，笔者在工作中发现一个问题，即无法得到正常的OSPF路由。笔者现将OSPF协议排错的过程写下来，希望能与更多的朋友共享。　　 1、 现象描述 　　在下图中，两台路由器通过串口连接，在互连接口上运行OSPF协议。RouterA的以太网接口地址为111.111.111.1，且运行了OSPF协议，Router的以太网接口地址为222.222.222.1，也启用了OSPF协议。 [attach]731[/attach] 　　RouterA的主要配置如下： 　　interface Loopback0 　　ip address 197.7.1.1 255.255.255.255 　　! 　　interface FastEthernet0/0 　　ip address 111.111.111.1 255.255.255.0 　　ip ospf cost 200 　　duplex auto 　　speed auto 　　! 　　interface Serial1/0 　　ip address 100.1.0.1 255.255.0.0 　　ip ospf network point-to-multipoint 　　ip ospf cost 200 　　serial restart-delay 0 　　! 　　router ospf 22 　　router-id 197.7.1.1 　　log-adjacency-changes 　　network 100.1.0.1 0.0.0.0 area 0 　　network 111.111.111.1 0.0.0.0 area 0 　　neighbor 100.1.0.2 cost 200 　　Router的主要配置如下： 　　interface FastEthernet0/0 　　ip address 222.222.222.1 255.255.255.0 　　ip ospf cost 200 　　duplex auto 　　speed auto 　　! 　　interface Serial1/0 　　ip address 100.1.0.2 255.255.0.0 　　ip ospf network non-broadcast 　　ip ospf cost 200 　　serial restart-delay 0 　　router ospf 22 　　router-id 197.7.1.2 　　log-adjacency-changes 　　network 100.1.0.2 0.0.0.0 area 0 　　network 222.222.222.1 0.0.0.0 area 0 　　neighbor 100.1.0.1 cost 200 　　故障现象如下： 　　在RouterA和RouterB上查看路由表，发现相互之间并没有学习到OSPF路由。 2、 显示OSPF信息 　　分别在两台路由器上查看邻居状态，显示如下： 　　RouterA#show ip ospf neighbor 　　Neighbor ID Pri State Dead Time Address Interface 　　197.7.1.2 0 FULL/ - 00:01:38 100.1.0.2 Serial1/0 　　RouterA#show ip ospf neighbor 　　Neighbor ID Pri State Dead Time Address Interface 　　197.7.1.1 1 FULL/BDR 00:01:54 100.1.0.1 Serial1/0 　　然后分别察看路由表，有下列显示： 　　RouterA#show ip route 　　100.0.0.0/16 is subnetted, 1 subnets 　　C 100.1.0.0 is directly connected, Serial1/0 　　197.7.1.0/32 is subnetted, 1 subnets 　　C 197.7.1.1 is directly connected, Loopback0 　　111.0.0.0/24 is subnetted, 1 subnets 　　C 111.111.111.0 is directly connected, FastEthernet0/0 　　RouterB#show ip route 　　C 222.222.222.0/24 is directly connected, FastEthernet0/0 　　100.0.0.0/16 is subnetted, 1 subnets 　　C 100.1.0.0 is directly connected, Serial1/0 　　接下来在来查看两台路由器的接口状态如下： 　　RouterA#show ip ospf interface 　　FastEthernet0/0 is up, line protocol is up 　　Internet Address 111.111.111.1/24, Area 0 　　Process ID 22, Router ID 197.7.1.1, Network Type BROADCAST, Cost: 200 　　Transmit Delay is 1 sec, State DR, Priority 1 　　Designated Router (ID) 197.7.1.1, Interface address 111.111.111.1 　　No backup designated router on this network 　　Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 　　oob-resync timeout 40 　　Hello due in 00:00:09 　　Index 2/2, flood queue length 0 　　Next 0x0(0)/0x0(0) 　　Last flood scan length is 0, maximum is 0 　　Last flood scan time is 0 msec, maximum is 0 msec 　　Neighbor Count is 0, Adjacent neighbor count is 0 　　Suppress hello for 0 neighbor(s) 　　Serial1/0 is up, line protocol is up 　　Internet Address 100.1.0.1/16, Area 0 　　Process ID 22, Router ID 197.7.1.1, Network Type POINT_TO_MULTIPOINT, Cost: 200 　　Transmit Delay is 1 sec, State POINT_TO_MULTIPOINT, 　　Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5 　　oob-resync timeout 120 　　Hello due in 00:00:23 　　Index 1/1, flood queue length 0 　　Next 0x0(0)/0x0(0) 　　Last flood scan length is 1, maximum is 1 　　Last flood scan time is 0 msec, maximum is 0 msec 　　Neighbor Count is 1, Adjacent neighbor count is 1 　　Adjacent with neighbor 197.7.1.2, cost is 200 　　Suppress hello for 0 neighbor(s) 　　RouterB#show ip ospf interface 　　FastEthernet0/0 is up, line protocol is up 　　Internet Address 222.222.222.1/24, Area 0 　　Process ID 22, Router ID 197.7.1.2, Network Type BROADCAST, Cost: 200 　　Transmit Delay is 1 sec, State DR, Priority 1 　　Designated Router (ID) 197.7.1.2, Interface address 222.222.222.1 　　No backup designated router on this network 　　Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 　　oob-resync timeout 40 　　Hello due in 00:00:07 　　Index 2/2, flood queue length 0 　　Next 0x0(0)/0x0(0) 　　Last flood scan length is 0, maximum is 0 　　Last flood scan time is 0 msec, maximum is 0 msec 　　Neighbor Count is 0, Adjacent neighbor count is 0 　　Suppress hello for 0 neighbor(s) 　　Serial1/0 is up, line protocol is up 　　Internet Address 100.1.0.2/16, Area 0 　　Process ID 22, Router ID 197.7.1.2, Network Type NON_BROADCAST, Cost: 200 　　Transmit Delay is 1 sec, State DR, Priority 1 　　Designated Router (ID) 197.7.1.2, Interface address 100.1.0.2 　　Backup Designated router (ID) 197.7.1.1, Interface address 100.1.0.1 　　Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5 　　oob-resync timeout 120 　　Hello due in 00:00:17 　　Index 1/1, flood queue length 0 　　Next 0x0(0)/0x0(0) 　　Last flood scan length is 1, maximum is 1 　　Last flood scan time is 0 msec, maximum is 0 msec 　　Neighbor Count is 1, Adjacent neighbor count is 1 　　Adjacent with neighbor 197.7.1.1 (Backup Designated Router) 　　Suppress hello for 0 neighbor(s) 　　3、原因分析 　　从查看路由器相应接口配置和状态信息来看，RouterA和Router相连接口的OSPF网络类型并不一致，因此导致路由计算错误，无法得到正常的OSPF路由。 　　4、处理过程 　　在RouterA和RouterB上，将相应的端口网络类型改为一致，就可以学习到正常的OSPF路由。改变Router的serial1/0口的网络类型为POINT_TO_MULTIPOINT 　　改正完成后，我们在来看下两台路由器的路由表： 　　RouterA#show ip route 　　O 222.222.222.0/24 [110/400] via 100.1.0.2, 00:00:33, Serial1/0 　　100.0.0.0/8 is variably subnetted, 2 subnets, 2 masks 　　C 100.1.0.0/16 is directly connected, Serial1/0 　　O 100.1.0.2/32 [110/200] via 100.1.0.2, 00:00:33, Serial1/0 　　111.0.0.0/24 is subnetted, 1 subnets 　　C 111.111.111.0 is directly connected, FastEthernet0/0 　　RouterB# show ip route 　　C 222.222.222.0/24 is directly connected, FastEthernet0/0 　　100.0.0.0/8 is variably subnetted, 2 subnets, 2 masks 　　O 100.1.0.1/32 [110/200] via 100.1.0.1, 00:00:31, Serial1/0 　　C 100.1.0.0/16 is directly connected, Serial1/0 　　111.0.0.0/24 is subnetted, 1 subnets 　　O 111.111.111.0 [110/400] via 100.1.0.1, 00:00:31, Serial1/0