SLIP(8)SLIP(8)NAMEslip - Serial Line IP
SYNOPSISslip pseudo-ip-device
DESCRIPTION
The slip program implements an Internet network connection over a bidi‐
rectional 8-bit transport, usually a serial line. The protocol used
for this connection is the Serial Line Internet Protocol, SLIP for
short.
The pseudo-ip-device argument names one of the /dev/psip* devices that
is offered by the MINIX 3 TCP/IP driver inet(8). The slip program
reads IP packets from standard input and writes them to the pseudo IP
device, and reads packets from the pseudo IP device and writes them to
standard output. A typical use is like this:
{
stty raw 115200
slip /dev/psip2 &
} </dev/tty01 >/dev/tty01
The SLIP protocol is just a very simple packet framing protocol. It
defines two characters as markers on a byte stream to frame packets.
SLIP does not implement any higher level addressing, error detection,
or compression. Thanks to its simplicity it can be used under MINIX 3,
any other system would prefer to use the Point-to-Point protocol: PPP.
The SLIP packet framing protocol as defined in RFC-1055 is as follows:
- Packets are delimited by an END character, octal 300. END is
often send at the start of a packet too to reset the logic of
the receiver, so that random noise isn't added to the beginning
of a packet.
- An ESC character (octal 333) is used to escape any END or ESC
characters that may occur in an IP packet. END and ESC are
changed to ESC 334 and ESC 335 in the data stream. (Note that
END doesn't occur within the data stream at all by escaping it
this way, making finding the framing END easier.)
FILES
/dev/psip* Pseudo-IP devices for use by slip.
SEE ALSO
RFC-1055.
NOTES
Under MINIX 3 slip forks in two to handle the two data streams in or
out of the serial line. Under Minix-vmd it uses asynchronous I/O to
handle the two streams within one program.
AUTHOR
Kees J. Bot <kjb@cs.vu.nl>
SLIP(8)
