Point-to-Point Protocol (PPP)

Giriş
Açıklaması şöyle

The roots of the Point-to-Point Protocol go back in time as far as 1989 where its first
standard RFC 1134 was adopted to provide a method for transmitting datagrams over serial point-to-point links. Since then, the standard got revised and extended multiple times. The current version of the basic protocol is described in RFC 1661. Besides an encapsulation methodology for multi-protocol data, it also comprises a stateful Link Control Protocol (LCP) component in order to monitor and manipulate the status of the link. It also includes an authentication process and an echo based probing mechanism. In addition, PPP supports a family of network layer control protocols for different network layer protocols, including IPCP for IP address exchange. Here, the
IP address of the PPP session peer is inserted into the local routing table.

PPP Layer 2'de çalışır. PPP istemcisi, sunucu ile oturum açtıktan sonra IP paketlerini kendi protokolü üzerinden alıp verir. Açıklaması şöyle

PPP was invented in the era of async-serial (RS-232) and dialup modems, and runs "naked" on those physical layers. As technology advanced, network operators wanted to continue using the same "dialup era" infrastructure and processes (i.e. account management), thus methods of carrying the familiar PPP were needed. An ethertype was registered for transporting PPP frames over ethernet. (and similar processes for ATM, and SONET. In the case of SONET, a bit of HDLC was needed to make the framing work with the SONET NRZ encoding.)

Eskiden telefon hattı üzerinden bağlantı (Dial up) için kullanılırdı. Günümüzde sanırım artık kullanılmıyor.