|  | 2.4 | WAN Encapsulation Formats
| 2.4.2 | PPP

PPP is a standard serial-line encapsulation method (described in RFC 1332 and RFC 1661). This protocol can, among other things, check for link quality during connection establishment. In addition, there is support for authentication through Password Authentication Protocol (PAP) and Challenge Handshake Authentication Protocol (CHAP).
| Engineering Journal
PPP Link Negotiation

| Web Links
| PPP