实验要求：使用OSPF路由协议，使每个路由器都能收集到所有网段
拓扑如下：
配置如下：
R1
enable
configure terminal
interface l0
ip address 192.168.10.1 255.255.255.0
interface s0/0/0
ip address 192.168.1.1 255.255.255.252
no shutdown
exit
router ospf 1
network 192.168.10.0 0.0.0.255 area 0
network 192.168.1.0 0.0.0.3 area 0
R2
enable
configure terminal
interface s0/0/0
ip address 192.168.1.2 255.255.255.252
clock rate 64000
no shutdown
interface s0/0/1
ip address 192.168.1.5 255.255.255.252
clock rate 64000
no shutdown
exit
router ospf 1
network 192.168.1.0 0.0.0.3 area 0
network 192.168.1.4 0.0.0.3 area 0
R3
enable
configure terminal
interface s0/0/1
ip address 192.168.1.6 255.255.255.252
no shutdown
interface s0/0/0
ip address 192.168.1.9 255.255.255.252
clock rate 64000
no shutdown
exit
router ospf 1
network 192.168.1.4 0.0.0.3 area 0
network 192.168.1.8 0.0.0.3 area 0
R4
enable
configure terminal
interface l0
ip address 192.168.20.1 255.255.255.0
interface s0/0/0
ip address 192.168.1.10 255.255.255.252
no shutdown
exit
router ospf 1
network 192.168.1.8 0.0.0.3 area 0
network 192.168.20.0 0.0.0.255 area 0