What is PPP?
PPP stands for point-to-point protocol, which is a technology for connecting to networks over standard serial (telephone) lines. In its most common implementation, users connect their personal computers to the Internet with PPP over a high-speed modem. It is similar to SLIP, but is more fully-featured and robust, providing error-checking and supporting the PAP and CHAP models of authentication.
Unlike programs such as ZTerm and Telix, which use your modem to connect to a terminal server, with PPP you have a more direct and flexible connection to the Internet. Many of the functions that you access by dialing up a terminal server and running them on a remote host (such as a Unix shell account), you can also do from your own computer. For instance, PPP allows you to use e-mail, news reading, and Web browser programs that take advantage of your workstation’s graphics capabilities, graphical user interface, etc.
Some examples of what a PPP connection allows:
- Telnet: Terminal connections to remote machines (essentially what terminal emulation programs like ZTerm and Telix allow)
- FTP: Transfer files between your machine and other machines on the Internet
- World Wide Web: Use a browser (e.g., Internet Explorer or Netscape Navigator or to access Web sites on the Internet
- Usenet: Use a newsreader to participate in Usenet newsgroups
- Ping: Find out if a machine on the Internet is “alive”
- Microsoft Networking: Access hard drives on other machines as though they were on your own
- AppleShare/IP: Connect to AppleShare/IP servers to access volumes, printers, and other devices from the Mac OS
- E-mail: Allows you to use fuller-featured mailer programs such as Eudora Outlook Express, and Pegasus
For a technical review of the PPP standard, read RFC 1661.
What is SLIP?
SLIP stands for Serial Line Internet Protocol. It runs the standard TCP and IP protocols over a serial link instead of over the Ethernet port on the back of your workstation. Basically, it means using a serial port as a slow network interface port.
Most ISP’s do not provide SLIP service due to an incompatibility with dial in servers.