http://www.rfc-editor.org/rfc/rfc1570.txt
RFC 1570: PPP LCP Extensions, W. Simpson1994-01-01T23:00:00-00:00The Point-to-Point Protocol (PPP) provides a standard method for transporting multi-protocol datagrams over point-to-point links. PPP defines an extensible Link Control Protocol (LCP) for establishing, configuring, and testing the data-link connection. This document defines several additional LCP features which have been suggested over the past few years. [STANDARDS-TRACK]