Just like heads in times of crisis, computers are most efficient when they
share their contents and work together. Most people -- or those who occupy
office cubicles during the daytime, anyway -- are used to working on PCs that
partake of networks; but most people don? know the first thing about what makes
such networks tick. What are nodes? Where do hubs reside? Who's afraid of data
collisions? These questions and more will be answered in the following
introductory segment on the ethereal art of linking computers to computers.
First and foremost, you should know what Ethernet refers to. Ethernet is the
name given to a standard of intra-computer communication. It was invented by one
Robert Metcalfe back in 1973, and its versatility and ability to adapt into
larger and larger networks has allowed it to survive to this day. There are
other types of computer networks out there, but Ethernet is by far the most
So how does it work?
Ethernet essentially specifies that two or more computers transmit
information back and forth in small chunks called packets. In order to avoid
data collisions (which occur when one packet is sent out at the same time as
another, and the two go Boom, and consequently fail to transmit), Ethernet
prescribes that each computer "look both ways before crossing" the cable.
Instead of merely sending out messages as soon as a user instructs their PC to
do so, Ethernet computers check their lines for concurrent transmissions, and
delay transmitting until lines are clear, in order to avoid data collisions.
Other attractions of the Ethernet system include the ability to send and
receive data at any time, whether the network's idle or active. Other types of
networks offer only intermittent intervals during which it's possible to
transmit information between member PCs. Moreover, Ethernet is affordable;
operates on any type of computer; and (best of all) allows each network member
to use the full bandwidth of the network. This means downloading times and
capacities are at their maximum, even though more than one party is sharing in
So what do you need?
First off -- surprise, surprise -- you need more than one computer. The second
item on your Ethernet shopping list should be a NIC card (network interface
card) which translates signals from your PC to the rest of the network, and back
again. Thirdly, don't try networking without a few switches. Their job is to
regulate traffic on the network. They are electronic devices, and they work like
customs officials. Each packet of transmitted data is inspected and then sent
off to its destination by switches. Fourthly, switches often work in conjunction
with hubs. Hubs receive packets that switches pass on to them, and then relay
those packets to the appropriate PC. A final handy item on your list is the
repeater -- a device that extends the range of most networks by amplifying, or
repeating, signals passed between computers. The size of most networks is
limited due to limitations in cabling; but repeaters foil this restriction and,
in effect, allow separate networks to act as cohesive units.
The process by which all this hardware relays data is, well, seven-fold.
There are generally seven "layers" through which each transmission must pass as
it travels from one computer to another. As you transfer a file from your PC to
a co-worker's PC, for instance, that file is broken down in seven different
stages, and then reconfigured at your colleague's end. While it would be tedious
to describe those seven stages here, it might be profitable to describe the
three types of cable that can be used to connect Ethernet networks. The original
Ethernet networks used coaxial cable -- the kind that links you to a cable TV
service at home. The two types of coaxial cable can support either 30 or 100
devices (computers, printers, and such) and span lengths of up to 606.9 feet or
1,640 feet, respectively. A more common form of Ethernet cabling is the
twisted-pair wire, which resembles telephone cords and also comes in a variety
of length/capacity flavours. The most efficient species of cable is the
fiber-optic kind, which is immune to electromagnetic interference (a problem
with some of the twisted-pair wire cables), and supports the biggest bandwidth
of any cable yet.
So long as people work together, networks will help them pass the work
around. Whether Ethernet will always be the premier paradigm for connection is
another matter. But given that it's been around for almost 30 years already,
chances are it isn's going anywhere in the next decade or so. So what are you
waiting for? It's a great day to send data, or receive it --