OSPF案例分析之如何得到正常ospf路由

ZDNet软件频道 时间:2009-12-06 作者: | 论坛整理 我要评论()
本文关键词:网络技术 OSPF 路由协议
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。
 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。

   
    
     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


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