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查看回复