Authenticate-Request
Authenticate-Ack or
Authenticate-Nak
Configuring PAP authentication is a pretty straightforward process. Here’s an example:
Router#config t
Router(config)#username todd password cisco
Router(config)#interface bri0
Router(config-if)#encapsulation ppp
Router(config-if)#ppp authentication pap
Router(config-if)#^Z
Router#