要求：全网互通
[R1]
[R1]INT E0/0/0
[R1-Ethernet0/0/0]ip address 13.1.1.1 24
[R1-Ethernet0/0/0]int e0/0/1
[R1-Ethernet0/0/1]ip address 12.1.1.1 24
[R1-Ethernet0/0/1]q
[R1]ospf 1 router-id 1.1.1.1（ospf的router-id）
[R1-ospf-1]area 0（为骨干区域，创建area 0）
[R1-ospf-1-area-0.0.0.0]network 13.1.1.0 0.0.0.255（宣告属于area0区域的接口）
[R1-ospf-1-area-0.0.0.0]network 12.1.1.0 0.0.0.255
[R2]
[R2]int e0/0/0
[R2-Ethernet0/0/0]ip address 24.1.1.2 24
[R2-Ethernet0/0/0]int e0/0/1
[R2-Ethernet0/0/1]ip address 12.1.1.2 24
[R2-Ethernet0/0/1]q
[R2]ospf 1 router-id 2.2.2.2
[R2-ospf-1]area 0
[R2-ospf-1-area-0.0.0.0]network 12.1.1.0 0.0.0.255
[R2-ospf-1-area-0.0.0.0]network 24.1.1.0 0.0.0.255
[R3]
[R3]int e0/0/0
[R3-Ethernet0/0/0]ip address 13.1.1.3 24
[R3-Ethernet0/0/0]int e0/0/1
[R3-Ethernet0/0/1]ip address 34.4.4.3 24
[R3-Ethernet0/0/1]q
[R3]ospf 1 router-id 3.3.3.3
[R3-ospf-1]area 0
[R3-ospf-1-area-0.0.0.0]network 13.1.1.0 0.0.0.255
[R3-ospf-1-area-0.0.0.0]network 34.1.1.0 0.0.0.255
[R4]
[R4]int e0/0/0
[R4-Ethernet0/0/0]ip address 34.1.1.4 24
[R4-Ethernet0/0/0]int e0/0/1
[R4-Ethernet0/0/1]ip address 24.1.1.4 24
[R4-Ethernet0/0/1]q
[R4]ospf 1 router-id 4.4.4.4
[R4-ospf-1]area 0
[R4-ospf-1-area-0.0.0.0]network 34.1.1.0 0.0.0.255
[R4-ospf-1-area-0.0.0.0]network 24.1.1.0 0.0.0.255
