You can do network installations over 3 types of communications links:

        Serial port:    SLIP / PPP
        Parallel port:  PLIP (laplink cable)
        Ethernet:       A standard ethernet controller (includes some PCMCIA).

SLIP support is rather primitive and limited primarily to hard-wired
links, such as a serial cable running between a laptop computer and
another PC.  The link must be hard-wired as the SLIP installation
doesn't currently offer a dialing capability; that facility is provided
with the PPP utility, which should be used in preference to SLIP
whenever possible.  When you choose a serial port device, you'll
be given the option later to edit the slattach command before it's
run on the serial line.  It is expected that you'll run slattach
(or some equivalent) on the other end of the link at this time and
bring up the line.  FreeBSD will then install itself over the link
at speeds of up to 115.2K/baud (the recommended speed for a hardwired
cable).

If you're using a modem then PPP is almost certainly your only
choice.  Make sure that you have your service provider's information
handy as you'll need to know it fairly early in the installation
process.  You will need to know, at the minimum, your service
provider's IP address and possibly your own (though you can also leave
it blank and allow PPP to negotiate it with your ISP).  You will also
need to know how to use the various "AT commands" to dial the ISP with
your particular brand of modem as the PPP dialer provides only a very
simple terminal emulator and has no "modem capabilities database".

If a hard-wired connection to another FreeBSD (2.0R or later) machine
is available, you might also consider installing over a "laplink"
parallel port cable.  The data rate over the parallel port is much
higher than what is typically possible over a serial line with
speeds of up to 50k/sec.

Finally, for the fastest possible network installation, an ethernet
adaptor is always a good choice!  FreeBSD supports most common PC
ethernet cards, a table of which is provided in the FreeBSD
Hardware Guide (see the Documentation menu on the boot floppy).
If you are using one of the supported PCMCIA ethernet cards, also be
sure that it's plugged in _before_ the laptop is powered on!  FreeBSD
does not, unfortunately, currently support "hot insertion" of PCMCIA
cards.

You will also need to know your IP address on the network, the "netmask"
value for your address class, and the name of your machine.
Your system administrator can tell you which values to use for your
particular network setup.  If you will be referring to other hosts by
name rather than IP address, you'll also need a name server and
possibly the address of a gateway (if you're using PPP, it's your
provider's IP address) to use in talking to it.  If you do not know
the answers to all or most of these questions, then you should
really probably talk to your system administrator _first_ before
trying this type of installation!