[Year 12 Its] Ongoing misinformation about topology

[Frank Van Den Boom]

There have been several discussions over the past couple of years
concerning the poor understanding and confusion about network topology
in texts, exam questions etc. I was looking forward to new editions of
the texts in the hope that we would finally get it right.

I was going through page proofs of the Thomson/Nelson book (new edition
of Building Information Systems), and this is what it says about Star
network topology.

"The most common topology is the star network. The main type of star
network has a central computer, usually a server computer, and all
computers and devices are connected directly to it. This configuration
is useful when the data to be used is required by many people and needs
to be centralised so that its integrity and security can be easily
managed. The access to the network is usually controlled by the network
operating system, that is run from the central computer.This topology
operates as a client/server network. A simple star network is a network
or segment of a network that is controlled by a switch or hub. In this
case the network is operating as a peer-to-peer network as there is no
central coordinating computer. There may be various servers operating on
the computers." 

I won't put in the text on Bus and Ring networks other than they do
focus more on the protocol and cabling topology. I don't know what the
above treatment of star network is based on and I find it all very
confusing. There are a ton of questions I would love to ask about this
paragraph. For starters - when was the last time any of us
saw/installed/used or even read about a star network where all the
devices were connected to a central computer? I won't bother with the
rest of the questions for now...

In looking at the new Janson/Dawson book, at least the focus is largely
on the protocol.
I have not looked at any other of the new books on this topic but I am
not confident that this confusion will go away.

So are we really clear on what we are teaching about "topology" ? I'm
not. The way the protocol works? The way the cabling is arranged?
Do we all realise that even 10 years ago, it was common to find a
24-port token ring hub, which used a star cabling topology to connect
its devices, which could have connected to it a bunch of PC's
functioning on a peer-to-peer basis as well as a database server which
was being used by the same PC's for a client-server application. 

So often, I read about this stuff in our IPM and IS texts in a way which
treats them all as mutually exclusive options.

The classic table that all of us have seen showing a list of advantages
and disadvantages for each of these topologies in many cases is just a
lot of rubbish in my view. For example, bus topologies are cheaper to
implement because they use less cable - might be true for coax but not
an old UTP/hub installation.

I just had a quick look at the VITTA Networking CD to see how it treats
protocol - more consistent in what it considers topology to be, but
there are still things there that are oversimplified. For example, "A
disadvantage of a ring topology is that if any device is added to or
removed from the ring, the ring is broken and the segment fails until it
is reconnected." In theory that is true, but most places would have used
a token ring hub for years, in which case it is irrelevant. But we are
not really in a position to show our students this when we teach it, and
it is also meaningless in my view.
I am not a trained communications person, and only built up an
understanding of some of these things in a large network environment
that I worked in a few years ago. So there is a good chance that some of
my definitions/understanding are not quite right. But I can assure you
that the IPM and IS books that I have used for the past 5 years have
done very little to clarify much of this.

It's probably too late for the authors of the new texts to review this
area. Is there some other way we can build a body of content that we
agree with, understand and can teach to kids in a meaningful way on this
subject?

Does anybody else out there feel the same way about this as me???

Frank

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