Because there may be a range of different computers, printers, modems,
etc on a network they all have to agree to 'speak the same language'
and also agree not to talk at the same time. For this to happen the
computers abide by certain rules ... which are called network protocols.
One of the rules in a protocol deals with how the computers introduce
themselves to each other, this is called handshaking.
One example of handshaking occurs each time you log onto the Internet:
your own home computer will handshake with the main computer owned by
your Internet Service