PAP Authenticate-ack and Authenticate-nak Frames

A PAP Authenticate-ack frame (code 0x02) is transmitted by the authenticator when it receives a recognizable PAP Authenticate-request frame that contains an acceptable PAP id and PAP password.

A PAP Authenticate-nak frame (code 0x03) is transmitted by the authenticator when it receives a PAP Authenticate-request frame that is not recognizable, or that contains an unacceptable PAP id and PAP password pair. The link is always terminated.