Password Authentication Protocols (PAP)

PAP  implements the  traditional username and password  authentication methods. At the  request from  an authenticator the client respond with both a PAP  name and password  in a single  transaction. The  authenticator validates this information and replies with a positive or negative acknowledgment. This  acknowledgment can  include readable text such as permission  granted or access denied .

PAP is the simplest  of the PAP authentication protocols  available. User credentials are transmitted in plain  text and only at  beginning of a PPP session. All the advantages and disadvantages of PSP  are identical to other dial up services secured with reusable usernames and passwords.

The PAP packet  format side a PPP appears  in the PPP frame  protocols  field is when it carries a PAP packet in its  data padding  fields. Any  LCP  negotiated change to the PPP frame format apply to frames that carry PAP. The PPP packet  code  field identifies the PPP message. The authentication request.

Packet include  fields  allocated for a username and password  packets for authentication ack  and authentication ank to authentication success and failure notifications. These packets have code values 0 x02 and 0x 03 respectively and include an explanatory text  message area  PPP  software  can use.