实例二、一端Unnumbered另一端Numbered
配置如下表：
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
