R1-R5 15.0.0.0
R2-R5 25.0.0.0
R3-R5 35.0.0.0
R4-R5 45.0.0.0
PC1--192.168.1.0
PC2--192.168.2.0
PC3--192.168.3.0
PC4--192.168.4.0
MGRE--192.168.5.0
GRE--192.168.6.0
[r5]aaa
[r5-aaa]local-user xx password cipher yy
[r5-aaa]local-user xx service-type ppp
[r5-Serial4/0/0]ppp authentication-mode pap
[r1-Serial4/0/0]ppp pap local-user xx password cipher yy
pap认证完成
[r5-Serial4/0/1]ppp authentication-mode chap
[r2-Serial4/0/0]ppp chap user xx
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