我司设备在于CISCO设备对接时，OSPF邻接无法建立。

在我司设备上敲指令”display ospf peer brief” ，显示： 

OSPF Process 10 with Router ID 10.1.1.1 
  Peer Statistic Information 
--------------------------------------------------------------------- 
Area Id          Interface                        Neighbor id      State    
--------------------------------------------------------------------- 

以往的案例中，我们一般会根据产品手册中提供的排障思路进行检测，在本次案例中我讲抛砖引玉用另外一种思路（debug）来定位 
在系统中依次输入指令， 
A． terminal monitor                   //使能终端显示信息中心发送信息的功能 
B． terminal debugging                 //使能终端显示Debug信息功能 
C． debugging ospf packet              //打开ospf的debug开关查看报文的收发情况 
我们可以看到下面的报文收发状态， 
Mar  4 2015 14:41:26.937.1-05:13 Huawei RM/6/RMDEBUG: 
FileID: 0xd0178024 Line: 2236 Level: 0x20 
OSPF 10: RECV Packet. Interface: GigabitEthernet0/0/0 
Mar  4 2015 14:41:26.937.2-05:13 Huawei RM/6/RMDEBUG:  Source Address: 10.1.1.2 
Mar  4 2015 14:41:26.937.3-05:13 Huawei RM/6/RMDEBUG:  Destination Address: 224.0.0.5 
Mar  4 2015 14:41:26.937.4-05:13 Huawei RM/6/RMDEBUG:  Ver# 2, Type: 1 (Hello) 
Mar  4 2015 14:41:26.937.5-05:13 Huawei RM/6/RMDEBUG:  Length: 44, Router: 10.1.1.2 
Mar  4 2015 14:41:26.937.6-05:13 Huawei RM/6/RMDEBUG:  Area: 0.0.0.0, Chksum:e59c 
Mar  4 2015 14:41:26.937.7-05:13 Huawei RM/6/RMDEBUG:  AuType: 00 
Mar  4 2015 14:41:26.937.8-05:13 Huawei RM/6/RMDEBUG:  Key(ascii): * * * * * * * 
Mar  4 2015 14:41:26.937.9-05:13 Huawei RM/6/RMDEBUG:  Net Mask: 255.255.255.252 
Mar  4 2015 14:41:26.937.10-05:13 Huawei RM/6/RMDEBUG:  Hello Int: 10, Option: _E 
Mar  4 2015 14:41:26.937.11-05:13 Huawei RM/6/RMDEBUG:  Rtr Priority: 1, Dead Int: 40 
Mar  4 2015 14:41:26.937.12-05:13 Huawei RM/6/RMDEBUG:  DR: 10.1.1.2 
Mar  4 2015 14:41:26.937.13-05:13 Huawei RM/6/RMDEBUG:  BDR: 0.0.0.0 
Mar  4 2015 14:41:26.937.14-05:13 Huawei RM/6/RMDEBUG:  # Attached Neighbors: 0 

FileID: 0xd0178025 Line: 559 Level: 0x20 
OSPF 10: SEND Packet. Interface: GigabitEthernet0/0/0 
Mar  4 2015 14:41:35.207.2-05:13 Huawei RM/6/RMDEBUG:  Source Address: 10.1.1.1 
Mar  4 2015 14:41:35.207.3-05:13 Huawei RM/6/RMDEBUG:  Destination Address: 224.0.0.5 
Mar  4 2015 14:41:35.207.4-05:13 Huawei RM/6/RMDEBUG:  Ver# 2, Type: 1 (Hello) 
Mar  4 2015 14:41:35.207.5-05:13 Huawei RM/6/RMDEBUG:  Length: 44, Router: 10.1.1.1 
Mar  4 2015 14:41:35.207.6-05:13 Huawei RM/6/RMDEBUG:  Area: 0.0.0.0, Chksum: e56c 
Mar  4 2015 14:41:35.207.7-05:13 Huawei RM/6/RMDEBUG:  AuType: 00 
Mar  4 2015 14:41:35.207.8-05:13 Huawei RM/6/RMDEBUG:  Key(ascii): * * * * * * * 
Mar  4 2015 14:41:35.207.9-05:13 Huawei RM/6/RMDEBUG:  Net Mask:255.255.255.252 
Mar  4 2015 14:41:35.207.10-05:13 Huawei RM/6/RMDEBUG:  Hello Int: 20, Option: _E 
Mar  4 2015 14:41:35.207.11-05:13 Huawei RM/6/RMDEBUG:  Rtr Priority: 1, Dead Int: 80 
Mar  4 2015 14:41:35.207.12-05:13 Huawei RM/6/RMDEBUG:  DR: 10.1.1.1 
Mar  4 2015 14:41:35.207.13-05:13 Huawei RM/6/RMDEBUG:  BDR: 0.0.0.0 
Mar  4 2015 14:41:35.207.14-05:13 Huawei RM/6/RMDEBUG:  # Attached Neighbors: 0 
Mar  4 2015 14:41:35.207.15-05:13 Huawei RM/6/RMDEBUG: 
我们对比一下收发报文的异同，发现我们接收对端的hello报文间隔为10S，我们发送的报文间隔为20S，是两端hello报文发送间隔不同导致邻居关系无法建立。 
D. undo debuging all                         //关闭debug功能

两端hello报文发送间隔不同导致邻居关系无法建立

将我司设备hello报文间隔调整为20S，问题解决。 
# 
Interface GigabitEthernet0/0/0 
ospf timer hello 20

在处理故障问题时，不防参考以下步骤进行排查：

1. 检查接口网段是否一致

2. 检查各接口的优先级是否有非零

3. 检查各路由器的route id互不相同

4. 接口的timer等参数保持一致

5. 接口的认证信息保持一致

6. 检查是否ospf报文能正确接收