[Year 12 Its] Ongoing misinformation about topology

[Don Morelli Edumail]

I agree that the books are very vague about networks and we can complain to
the authors and I assume that many have, but it doesn't seem to be doing
much to improve what is being written about this topic.

We need to remember that when we are dealing with the concept of networks,
that we cover the 3 areas of topology, protocol and type of network
separately and then the relationship between them. We then also need to
cover what is commonly used in organisations today (hybrid). Often the books
will say that a star network has a central fileserver, which is confusing
the topology (star network) and the type of network (possibly client
server). We need to make sure that the kids know the difference between
these 3 areas and don't confuse them further by only having the books as
examples.

I did not know until about 2 years ago that token ring was named for the
protocol and not for the topology (star). I thought that it used a token
passing protocol on a ring topology. These lists are fantastic for clearing
up any misconceptions that we have, as it did for me, so keep posting and
people in the know will keep answering. 

If we get these clear in our own minds then we won't confuse the kids.

Cheers Don Morelli

  _____  

From: is-bounces at edulists.com.au [mailto:is-bounces at edulists.com.au] On
Behalf Of Frank Van Den Boom
Sent: Wednesday, 16 August 2006 12:36 PM
To: is at edulists.com.au
Subject: [Year 12 Its] Ongoing misinformation about topology

 

 

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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Information Technology Teachers Association Inc



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