测试要求：shutdown s0接口再no shut s0接口后ping 12.1.1.1
R1：hostname R1username R2 password ciscointerface Serial0/0ip address 12.1.1.1 255.255.255.0encapsulation pppclockrate 64000ppp authentication chap
R2：host R2username R1 password ciscointerface Serial0ip address 12.1.1.2 255.255.255.0encapsulation pppclockrate 64000ppp authentication chap
用定义好的用户名user1来验证：
R1：username R2 password 0 ciscohostname R1interface Serial0/0ip address 12.1.1.1 255.255.255.0encapsulation pppclockrate 64000ppp authentication chapppp chap hostname user1
R2：username user1 password ciscohost R2interface Serial0ip address 12.1.1.2 255.255.255.0encapsulation pppclockrate 64000ppp authentication chap
R1要求验证,R2不要求验证:
R1：hostname R1username R2 password 0 ciscointerface Serial0/0ip address 12.1.1.1 255.255.255.0encapsulation pppclockrate 64000ppp authentication papppp pap sent-username R1 password 0 cisco
R2：hostname R2username R1 password 0 ciscointerface Serial0ip address 12.1.1.2 255.255.255.0encapsulation pppppp authentication papppp pap sent-username R2 password 0 cisco
用定义好的用户名user1来验证：
R1：hostname R1username user1 password 0 ciscointerface Serial0/0ip address 12.1.1.1 255.255.255.0encapsulation pppclockrate 64000ppp authentication papppp pap sent-username R1 password 0 cisco
R2：hostname R2username R1 password 0 ciscointerface Serial0ip address 12.1.1.2 255.255.255.0encapsulation pppppp authentication papppp pap sent-username user1 password 0 cisco
R1要求验证,R2不要求验证:
R1：username R2 password 0 ciscohostname R1interface Serial0/0ip address 12.1.1.1 255.255.255.0encapsulation pppclockrate 64000ppp authentication pap
R2：hostname R2interface Serial0ip address 12.1.1.2 255.255.255.0encapsulation pppppp pap sent-username R2 password 0 cisco
