介绍：本文档介绍了对OSPF的一些常见问题进行TS的一个简单的工作流程。要了解更详细的信息请点击流程图中的红色字样
OSPF的整个TS流程如下图所示：
准确地分析症状，这是一切的开始。 这标志着ospf的数据包被第二层或软件所修改，如出现：”ospf-4-badlsa type-error” 果发送者在发送类型为6的Mospf包，你可以通过配置Ignore lsa mospf来忽略它 在启用ospf前，至少需要有一个配置好了IP地址的在配置OSPF时出现：”can’t allocate router-id” 接口的处于活跃状态。确认至少有一个接口牌活跃状态。 出现：“ospf-4-errrcv”信息 请参照“OSPF-4-ERRRCV”的含义一文。 否 仔细检查配置，一个最可能的原因是在redistribute命令中忘记写subnets关键字了 其它路由条目不能 被重分布进OSPF进程 该路由条目是缺省是 请参照OSPF如何产生缺省路由一文。 请参照在是 配置OSPF时出现：”ospf unkown procotol” 1600或800路由器上配置OSPF1600或的注意事项一文。 800路由否 检查你的软件版本，向吧。 ultra技术支持中心求救OSPF不能建立起完全邻接关系（注意：在secondary networks上是本就不能邻接） 请参照OSPF邻接状态一文。
路由表中看不到OSPF的路由条目。 请参照OSPF路由检查一文。
OSPF故障排除实例分析
http://www.UltraTechnology.net/ 2002-12-19 juechen70 原创/编译 未经许可,严禁转载
实例一 网络类型不一致 拓朴如下图所示：
配置如下表所示：
Route1 interface Loopback0
ROUTE2 interface Loopback0 ip address 10.1.3.1 255.255.255.255 ! interface Serial1/1 ip address 10.1.1.2 255.255.255.0 clockrate 64000 router ospf 20 network 10.1.0.0 0.0.255.255 area 0 ip address 10.1.2.1 255.255.255.255 interface Serial1 ip address 10.1.1.1 255.255.255.0 ip ospf network broadcast router ospf 20 network 10.1.0.0 0.0.255.255 area 0
ROUTE1#show ip ospf interface serial 1 Serial1 is up, line protocol is up Internet Address 10.1.1.1/24, Area 0
Process ID 20, Router ID 10.1.2.1, Network Type BROADCAST, Cost: 64 Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 10.1.2.1, Interface address 10.1.1.1 Backup Designated router (ID) 10.1.1.2, Interface address 10.1.1.2 Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:08
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 10.1.1.2 (Backup Designated Router) Suppress hello for 0 neighbor(s) ROUTE2#show ip ospf interface serial 1/1
Serial1/1 is up, line protocol is up Internet Address 10.1.1.2/24, Area 0
Process ID 20, Router ID 10.1.1.2, Network Type POINT_TO_POINT, Cost: 64 Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:02
Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 10.1.2.1 Suppress hello for 0 neighbor(s)
从上面可以看出，路由器Router1是配置broadcast模式，而路由器Roure2配置成点对点模块。这种网络类型的不匹配，导致了路由通告的不可达。
ROUTE1#show ip ospf database router 10.1.1.2 Adv Router is not-reachable LS age: 418
Options: (No TOS-capability, DC) LS Type: Router Links Link State ID: 10.1.1.2 Advertising Router: 10.1.1.2 LS Seq Number: 80000002 Checksum: 0xFA63 Length: 60 Number of Links: 3
Link connected to: another Router (point-to-point) (Link ID) Neighboring Router ID: 10.1.2.1 (Link Data) Router Interface address: 10.1.1.2 Number of TOS metrics: 0 TOS 0 Metrics: 64
Link connected to: a Stub Network (Link ID) Network/subnet number: 10.1.1.0 (Link Data) Network Mask: 255.255.255.0 Number of TOS metrics: 0 TOS 0 Metrics: 64
ROUTE2#show ip ospf database router 10.1.2.1 Adv Router is not-reachable LS age: 357
Options: (No TOS-capability, DC) LS Type: Router Links Link State ID: 10.1.2.1 Advertising Router: 10.1.2.1 LS Seq Number: 8000000A
Checksum: 0xD4AA Length: 48 Number of Links: 2
Link connected to: a Transit Network (Link ID) Designated Router address: 10.1.1.1 (Link Data) Router Interface address: 10.1.1.1 Number of TOS metrics: 0 TOS 0 Metrics: 64
可以看出，对于子网10.1.1.0/24, 路由器ROUTE2产生一个点对点连接，而路由器Router2则产生一个透过的连接，这就在链路状态数据库中产了不一致，从而导致路由信息不会出现在路由表中。 ROUTE2#show ip route
10.1.0.0/16 is variably subnetted, 3 subnets, 2 masks C 10.1.1.0/24 is directly connected, Serial1/1 C 10.1.3.1/32 is directly connected, Loopback0 解决方案：
为了解决这个问题，需要将两边的网络类型配置为一致。既可以将Router1上的网络类型改为点对点，也可以将Router2上的网络类型改为broadcast.在这个例子中我们将Router1上的网络类型修改为点对点类型。
ROUTE1#configure terminal ROUTE1(config)#interface serial 1
ROUTE1(config-if)#no ip ospf network broadcast ROUTE1(config-if)#end
ROUTE1#show ip ospf interface serial 1 Serial1 is up, line protocol is up Internet Address 10.1.1.1/24, Area 0
Process ID 20, Router ID 10.1.2.1, Network Type POINT_TO_POINT, Cost: 64 Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:04
Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 10.1.1.2 Suppress hello for 0 neighbor(s) 至此，故障排除。
需要注意的是，如果有一端的接口是多接口，而另一端是子接口，那么需要将两边都修改为broadcast接口。
实例二、一端Unnumbered另一端Numbered 拓朴如下图所示:
配置如下表： ROUTER1 ROUTER2 interface Loopback0 interface Loopback0 ip address 10.1.2.1 255.255.255.255 interface Serial1 ip unnumbered Loopback0 router ospf 20 network 10.1.0.0 0.0.255.255 area 0 ip address 10.1.3.1 255.255.255.255 ! interface Serial1/1 ip address 10.1.1.2 255.255.255.0 clockrate 64000 router ospf 20 network 10.1.0.0 0.0.255.255 area 0 ROUTER1#show interface serial 1 Serial1 is up, line protocol is up Hardware is cxBus Serial
Interface is unnumbered. Using address of Loopback0 (10.1.2.1) ROUTER2#show interface serial 1/1 Serial1/1 is up, line protocol is up Hardware is cxBus Serial Internet address is 10.1.1.2/24
上面的输出显示出ROUTER1的Serial 1接口是个unnumbered 接口，使用Loopback0的地址,而ROUTER2的Serial 1/1则配置有IP地址。
ROUTER1#show ip ospf interface serial 1 Serial1 is up, line protocol is up Internet Address 0.0.0.0/24, Area 0
Process ID 20, Router ID 10.1.2.1, Network Type POINT_TO_POINT, Cost: 64 Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:02
Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 10.1.1.2 Suppress hello for 0 neighbor(s)
ROUTER2#show ip ospf interface serial 1/1 Serial1/1 is up, line protocol is up Internet Address 10.1.1.2/24, Area 0
Process ID 20, Router ID 10.1.1.2, Network Type POINT_TO_POINT, Cost: 64 Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:02
Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 10.1.2.1 Suppress hello for 0 neighbor(s)
从上面可以看出，两边的网络类型都是点对点的，出现问题的原因是一边是unnumbered 而另一边则配置有IP地址，这就造成了OSPF数据库中的不一致。 ROUTER1#show ip ospf database router 10.1.1.2 Adv Router is not-reachable LS age: 418
Options: (No TOS-capability, DC) LS Type: Router Links Link State ID: 10.1.1.2 Advertising Router: 10.1.1.2 LS Seq Number: 80000002 Checksum: 0xFA63 Length: 60 Number of Links: 3
Link connected to: another Router (point-to-point) (Link ID) Neighboring Router ID: 10.1.2.1 (Link Data) Router Interface address: 10.1.1.2 Number of TOS metrics: 0 TOS 0 Metrics: 64
ROUTER2#show ip ospf database router 10.1.2.1 Adv Router is not-reachable LS age: 357
Options: (No TOS-capability, DC) LS Type: Router Links Link State ID: 10.1.2.1 Advertising Router: 10.1.2.1 LS Seq Number: 8000000A Checksum: 0xD4AA Length: 48 Number of Links: 2
Link connected to: another Router (point-to-point) (Link ID) Neighboring Router ID: 10.1.1.2 (Link Data) Router Interface address: 0.0.0.4 Number of TOS metrics: 0
TOS 0 Metrics: 64
可以看见ROUTER1为这个点到点链路产生了一个包括它的接口地址信息的LSA，而Router2同样产生了一个包括IfIndex值的LSA，这就在链路状态数据库中产生了不一致，也就意味着路由信息不会在路由表中出现。从以下的命令可以看到：
ROUTER2#show ip route
10.1.0.0/16 is variably subnetted, 3 subnets, 2 masks C 10.1.1.0/24 is directly connected, Serial1/1 C 10.1.3.1/32 is directly connected, Loopback0 解决办法：
要解决这个问题，可以将两边路由器都楝配为unnumbered的，或者为两连路由器的接口都配置上IP地址。在这个例子中我们把Router1的serial1口配置上IP地址。 ROUTER1#configure terminal ROUTER1(config)#interface serial 1
ROUTER1(config-if)#no ip unnumbered loopback 0 ROUTER1(config-if)#ip address 10.1.1.1 255.255.255.0 ROUTER1)#show ip ospf interface serial 1 Serial1 is up, line protocol is up Internet Address 10.1.1.1/24, Area 0
Process ID 20, Router ID 10.1.2.1, Network Type POINT_TO_POINT, Cost: 64 Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:02
Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 10.1.1.2 Suppress hello for 0 neighbor(s) ROUTER2#show ip route
10.1.0.0/16 is variably subnetted, 3 subnets, 2 masks C 10.1.1.0/24 is directly connected, Serial1/1
O 10.1.2.1/32 [110/65] via 10.1.1.1, 00:03:08, Serial1/1 C 10.1.3.1/32 is directly connected, Loopback0 至此，问题解决。
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