As
promised several weeks ago I come back with a series of networking
guides. Ignored by most users and hardware resources (magazines,
sites), networking is the most important part of today technologies.
You probably know that without networking it would be impossible
to chat, use the net, use your mobile phone or even the cable television.
All major technologies today work on the concept of networking;
even if these are computer related or not. Your local GSM operator
has a network of "data communicating cells" and although
this network is different from a computer network it is based on
the same principles. We will mainly talk about computer networks
because this is my qualification but I do not exclude articles about
other types of networks in the future.
PC Hardware deals mainly with hardware, that's why I will refer
mainly to the hardware part of the network. However hardware and
software is directly related and it would be impossible not to mention
the software part, but you will not find out how to set your Linux/NT
server while reading this article. Instead I can promise that after
completing this networking series you will be able to design and
setup a reliable, expandable, safe network that can run any networking
software. I will present first the theoretical fundaments of networking.
But let's start with several historic issues.
In
the 80's when the idea of network gained more and more adepts engineers
understood that without a standardization of the network technology
further extension of the concept would had been foredoomed to failure.
International Organization for Standardization (ISO) researched
many network schemes to promote the one which would provide the
best interconectivity. So that in 1984 they created a network model
capable of helping companies to develop networks able to work together.
This model was called the OSI reference model and it was released
in 1984.
As you may know data travels by medium in bits, but a network unable
to connect a Macintosh computer to a PC machine wouldn't have been
too successful. ISO started from a very simple idea. They knew that
the best way to solve a technological problem is to inspire from
nature. When two people communicate they must go through several
phases:
- First it must appear the idea of communication (impulse).
- Second the man has to think to the representation of the idea.
If you are in front of your girlfriend you probably want to kiss
her, in front of your teacher I don't think that's the best idea.
- Third you have to think to a method of delivery: a normal kiss
is enough? If not what about a a French kiss?
- With all these prepared the physical action must occur: do it!
So
ISO decided to create a model using layers, each layer dealing with
another action, but all related between them because communication
without one of the above steps is impossible. In the above representation
there are only four steps, but ISO went for another, more detailed
scheme. The OSI layers (not ISO - International Standards Organization
) have a lot of advantages; one of them being that can be easily
taught. There is no professional network engineer in this world
without knowledge about OSI layers. It's impossible to develop networks
without knowing them. These layers are the foundation of the network.
The OSI reference model allows you to view the network functions
that occur at each layer level. The OSI reference model is a framework
that allows understanding the way data travels through a network.
In the OSI model there are seven different layers, everyone with
a specific function. We will see later that TCP/IP simplifies the
OSI reference model, but for the start we need knowledge of OSI.
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Tagan TG480-U01 480W ATX / EPS Power Supply Review 
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