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OSPF案例分析之如何得到正常的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

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