配置IP的地址

[R1-GigabitEthernet0/0/0]int g0/0/0
[R1-GigabitEthernet0/0/0]ip add 192.168.1.1 24
[R1-GigabitEthernet0/0/0]int s4/0/0
[R1-Serial4/0/0]ip add 15.0.0.1 24

[R2]int s 4/0/0
[R2-Serial4/0/0]ip add 25.0.0.1 24
[R2-Serial4/0/0]int g 0/0/0
[R2-GigabitEthernet0/0/0]ip add 192.168.2.1 24

[R3]int s 4/0/0
[R3-Serial4/0/0]ip add 35.0.0.1 24
[R3-Serial4/0/0]int g 0/0/0
[R3-GigabitEthernet0/0/0]ip add 192.168.3.1 24

[R4]int s 4/0/0
[R4-Serial4/0/0]ip add 45.0.0.1 24

[R4-Serial4/0/0]int g0/0/0
[R4-GigabitEthernet0/0/0]ip add 192.168.4.1 24

[R5]int s 3/0/0
[R5-Serial3/0/0]ip add 15.0.0.2 24
[R5-Serial3/0/0]int s 4/0/0
[R5-Serial4/0/0]ip add 25.0.0.2 24
[R5-Serial4/0/0]int s 4/0/1
[R5-Serial4/0/1]ip add 45.0.0.2 24
[R5-Serial4/0/1]int s 3/0/1
[R5-Serial3/0/1]ip add 35.0.0.2 24

[R5-Serial3/0/1]int l0
[R5-LoopBack0]ip add 5.5.5.5 24

R1和R5使用PAP认证，R5为主认证方

被认证方：

R1-Serial4/0/0]ppp pap local-user ywq  password cipher 123456
主认证方
[R5-aaa]local-user ywq password cipher 123456 
[R5-aaa]local-user ywq service-type ppp 

[R5-Serial3/0/0]ppp authentication-mode pap 

[R5-aaa]local-user ywq password cipher 123456
[R5-aaa]local-user ywq service-type ppp
[R5-aaa]int s0/0/3
[R5-Serial0/0/3]ppp authentication-mode pap

R1和R5使用chap认证，R5为主认证方

[R2]int s0/0/1
[R2-Serial0/0/1]ppp chap user ywq
[R2-Serial0/0/1]ppp chap  password cipher 123456