# slip(8)

    NAME
         slip - Serial Line IP

    SYNOPSIS
         slip pseudo-ip-device

    DESCRIPTION
         The slip  program  implements  an  Internet  network  connection  over  a
         bidirectional  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 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, 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 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>