PPP has been standardized through the IETF
process, so an excellent history of the evolution of the protocol has
been captured through the RFC series. Open development has also made
a number of good references readily available. I particularly
PPP Design, Implementation, and
Debugging, by James Carlson.
Documents listed in this section are of interest because they offer insight into the way the protocol evolved and the challenges facing protocol designers at the time. None of the RFCs in this section describe present standards, nor should they be used to guide any implementation efforts.
“A Nonstandard for Transmission of IP Datagrams Over Serial Lines: SLIP”
Despite the title, SLIP was the first standard method of transmitting IP over serial lines. It lacked framing, flow control, and the ability to send anything other than IP, but it was a start.
“Compressing TCP/IP Headers for Low-Speed Serial Links”
This RFC is unusual in that it is available in both ASCII text and PostScript, with the latter format having more detailed and prettier diagrams. In 1990, state of the art modems were far slower than they are today, and time-shared computing was a necessity for researchers needing even moderate power. One of SLIP’s many problems is that it transmitted full headers for both TCP and IP. Interactive connections frequently send packets with 1 or 2 bytes of data. LAN media can easily handle packets with 40-plus header ...