1.点对点
a、点对点不选举DR/BDR
b、区域内各个路由器都有一样的拓扑数据库
c、串口时钟由DCE端决定，需要为DCE端配置时钟
d、串口封装encaption ppp
e、查看邻居show ip ospf neighbor
f、查看拓扑数据库show ip ospf database
g、查看路由show ip route
R1配置
enconf thostname R1int s0/0ip address 192.168.1.1 255.255.255.0clock rate 64000enc pppno shutdownexitint loopback 0ip address 1.1.1.1255.255.255.0no shutdownexitrouter ospf 1network 1.1.1.00.0.0.255 area 0network 192.168.1.0 0.0.0.255area 0exitend
R2配置
enconf thostname R2int s0/0ip address 192.168.1.2 255.255.255.0enc pppno shutdownexitint s0/1ip address 192.168.2.1 255.255.255.0clock rate 64000enc pppno shutdownexitint loopback 0ip address 2.2.2.2255.255.255.0no shutdownexitintrouter ospf 1network 192.168.1.0 0.0.0.255area 0network 192.168.2.0 0.0.0.255area 0network 2.2.2.00.0.0.255 area 0exitend
R3配置
enconf thostname R3int s0/1ip address 192.168.2.2 255.255.255.0enc pppno shutdownexitint s0/0ip address 192.168.3.1 255.255.255.0clock rate 64000enc pppno shutdownexitint loopback 0ip address 3.3.3.3255.255.255.0no shutdownexitintrouter ospf 1network 192.168.2.0 0.0.0.255area 0network 192.168.3.0 0.0.0.255area 0network 3.3.3.00.0.0.255 area 0exitend
R4配置
enconf thostname R4int s0/0ip address 192.168.3.2 255.255.255.0enc pppno shutdownexitint loopback 0ip address 4.4.4.4255.255.255.0no shutdownexitrouter ospf 1network 192.168.3.0 0.0.0.255area 0network 4.4.4.00.0.0.255 area 0exitend
R1#show ip ospf neighbor
Neighbor ID PriState Dead Time Address Interface
2.2.2.2 0FULL/ - 00:00:36 192.168.1.2 Serial0/0
R1#show ip ospf database
OSPF Router with ID (1.1.1.1) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 56 0x80000003 0x003297 3
2.2.2.2 2.2.2.2 56 0x80000006 0x0085b5 5
3.3.3.3 3.3.3.3 56 0x80000006 0x00051e 5
4.4.4.4 4.4.4.4 56 0x80000003 0x009408 3
解释：show ipospf neighbor 显示邻居。FULL/-中-表示不选举DR/BDR。
show ip ospf database 只有LSA1
R1#show ip route
Codes: C - connected, S - static, I - IGRP,R - RIP, M - mobile, B - BGP
D - EIGRP, EX -EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 -OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPFexternal type 2, E - EGP
i - IS-IS, L1 -IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/24 is subnetted, 1 subnets
C1.1.1.0 is directly connected, Loopback0
2.0.0.0/32 is subnetted, 1 subnets
O2.2.2.2 [110/65] via 192.168.1.2, 00:01:15, Serial0/0
3.0.0.0/32 is subnetted, 1 subnets
O 3.3.3.3 [110/129] via 192.168.1.2,00:01:15, Serial0/0
4.0.0.0/32 is subnetted, 1 subnets
O 4.4.4.4 [110/193] via 192.168.1.2,00:01:15, Serial0/0
192.168.1.0/24 is variablysubnetted, 2 subnets, 2 masks
C192.168.1.0/24 is directly connected, Serial0/0
C192.168.1.2/32 is directly connected, Serial0/0
O192.168.2.0/24 [110/128] via 192.168.1.2, 00:01:15, Serial0/0
O192.168.3.0/24 [110/192] via 192.168.1.2, 00:01:15, Serial0/0
解释：C直连路由，O代表ospf产生的域内路由，由LSA1和LSA2产生。
