[pyr.syseng.comm] SLIP

csg@pyramid.pyramid.com (Carl S. Gutekunst) (09/01/88)

In article <1173@bellboy.UUCP> hack@bellboy.UUCP (Greg Hackney) writes:
>Could someone take the time to explain what SLIP is?
>Who wrote it? How does one get it? Does it run on the Pyramid? Others?

SLIP stands for Serial Line Internet Protocol. It allows IP to run on a tty
line, which implies TCP/IP, ftp, telnet, rlogin, rsh, rcp, etc. It provides a
strictly point-to-point link between two systems, where each end has its own
internet address. Magic in the routing tables can make a bunch of point-to-
point SLIP links look like a network. I even know of a few hardy souls who are
running NFS and PC NFS across 9600 baud links and TrailBlazers. We used it for
a while for an Internet connection to NASA Ames, via TrailBlazer. It was slow,
but very usable for SMTP, NNTP, and ftp.

SLIP was written by Rick Adams, with subsequent heavy modification by Chris
Torek. It is in the public domain, and versions are available for 4.2BSD and
4.3BSD on the VAX, 4.3BSD Tahoe, SunOS 3.5. (Beware, though: there is a bug in
the 4.3BSD routed(8) that breaks routing when using a Class B point-to-point
link. The recent Berkeley networking release fixed that problem.) SunOS 4.0
uses Guy Harris's Streams tty driver, so someone will have to do a Streams
version of SLIP (probably Guy :-)). There are also commercial versions for
MS-DOS, although I don't have information about that.

Pyraid ships SLIP with the NSP (Networking Software Package) option as of OSx
4.4. It is not available for earlier OSx releases. Pyramid does *not* claim to
support NFS over SLIP, so you're on your own there. But I've seen it work.

The only other vendor I know of for certain that ships a supported SLIP for
UNIX is Mt. Xinu. I've heard rumor that Celerity and Encore do as well. It is
used most heavily in University and DARPA sites, who generally have BSD source
code and can hack in the SLIP interface module themselves.