[Year 12 Its] Ongoing misinformation about topology

Allan Barnes abarnes at aiet.com.au
Sat Aug 26 08:47:28 EST 2006


No worries Anton. I will send you one as soon as it is completed - hopefully
Friday.


Kind regards


Allan Barnes, CEO
Australian Institute of Education and Training
Phone: (03) 9387 2051
FAX: (03) 9387 3470
E-mail: abarnes at aiet.com.au 

-----Original Message-----
From: is-bounces at edulists.com.au [mailto:is-bounces at edulists.com.au] On
Behalf Of Anton Yoxon
Sent: Friday, 25 August 2006 9:39 AM
To: Year 12 Information Technology Systems Teachers' Mailing List
Subject: RE: [Year 12 Its] Ongoing misinformation about topology


Alan, could you send a copy to me at South Oakleigh Secondary College as
well

Cheers

Anton Yoxon

On Fri, 25 Aug 2006 08:33:24 +1000, Allan Barnes wrote
> Hi Frank
> 
> I am just going through the final edit of the new edition of the 
> Navigating Informations Systems book so I have gone back and tried to 
> tidy up the network topology section as much as I can. Happy to send 
> you a copy of the book (and other schools that want to have a look at 
> it as well) in about a week when it has been published.
> 
> Kind regards
> 
> Allan Barnes, CEO
> Australian Institute of Education and Training
> Phone: (03) 9387 2051
> FAX: (03) 9387 3470
> E-mail: abarnes at aiet.com.au
> 
> -----Original Message-----
> From: is-bounces at edulists.com.au [mailto:is-bounces at edulists.com.au]
> On Behalf Of Kevork Krozian Sent: Tuesday, 22 August 2006 2:27 PM
> To: is at edulists.com.au Subject: Re: [Year 12 Its] Ongoing 
> misinformation about topology
> 
> Hi Frank,
> 
>      I share your frustration and have gone through the same journey.
> 
>  I would make a couple of points:
> 
>      1.  Even if books still think star networks have a central 
> computer, ignore it and teach as you know it to be. A star network has 
> a central concentration device . This is called a switch ( not a 
> computer unless you have 10, 20 or 30 network cards in them , and NOT 
> a hub because a hub is really a BUS network with the T-pieces of the 
> old BNC type connectors pulled into the hub ). With the computer with 
> the 30 network cards , this would make the concentration device a 
> ROUTER and not a switch.
> 
>    2. Whether an installation has a hybrid network or not is not the 
> point when discussing the definition of a star network. Nor is it the 
> point that a pure STAR network is less common than a hybrid network 
> when asking for a definition of a star network.
> 
>    3. As for a TOKEN RING network there are two aspects - the media 
> access method ( use of a token ) and the topology ( a ring ).
> 
>    4. There is a difference between a PHYSICAL topology ( a hub 
> presents as a physical star network ) and a LOGICAL topology (  a hub 
> is a logical BUS as all nodes are connected to the same wire ).
> And yes Don Morelli has accurately pointed out that a Token Ring is a 
> physical STAR and a logical RING . The media access method is by way 
> of a token. You need a token to communicate otherwise you are 
> listening.  The logical topology is a RING using a physical topology 
> of a STAR by way of a device called a MSAU - multi station access
> unit .      Now, I teach this concept no matter what the text books 
> or study design says. However others might argue it is too complex for 
> the students. In the same breath, this is EXACTLY what I teach my 
> Cisco CCNA students who are often the same faces who appear in my IT 
> Systems class.  So why is it too difficult for one and not the other ?
> 
>    5. If you want precise definitions and references to your key 
> points , ask a qualified , practicing network engineer working in the 
> field. He/she will tell you what is found out in industry and 
> education and other installations , and not what is written in books 
> that have information years out of date.  You can consult one or more 
> of these people on the cisco mailing list at www.edulists.com.au . 
> Subscribe the usual way.
> 
>     Hope this helped.
> 
> Best Wishes
> 
> Kevork Krozian
> IT Manager , Forest Hill College
> k.krozian at fhc.vic.edu.au
> http://www.fhc.vic.edu.au
> Mobile: 0419 356 034
> 
> >>> forster at ozonline.com.au 08/17/06 04:20pm >>>
> Its sad that a subject with such potential is being used for the rote 
> learning of definitions. Do we want walking dictionaries?
> "The mind is not a vessel to be filled but a fire to be kindled." 
> Plutarch
> (46 - 127)
> 
> ----- Original Message -----
> From: "Allan Barnes" <abarnes at aiet.com.au>
> To: "'Year 12 Information Technology Systems Teachers' Mailing List'" 
> <is at edulists.com.au> Sent: Thursday, August 17, 2006 12:08 PM
> Subject: RE: [Year 12 Its] Ongoing misinformation about topology
> 
> >I think the classic definition of a star topology is correct as you 
> >have  stated, however, as you have also stated, it is not often seen in
places.
> > Nowadays, it is more common to have hybrid networks that are a
combination
> > of a number of topologies, or two star networks stuck together, and 
> > so forth.
> >
> > If we are teaching the true meaning of a star network then 
> > essentially we have it right, but what we also need to be saying to 
> > our students is that the star topology is not generally found in 
> > industry and it is a mixture or hybrid.
> >
> >
> >
> >
> > Kind regards
> >
> >
> > Allan Barnes, CEO
> > Australian Institute of Education and Training
> > Phone: (03) 9387 2051
> > FAX: (03) 9387 3470
> > E-mail: abarnes at aiet.com.au
> >
> >
> >
> > -----Original Message-----
> > From: is-bounces at edulists.com.au [mailto:is-bounces at edulists.com.au] 
> > On Behalf Of a.hopkins at bcc.vic.edu.au
> > Sent: Thursday, 17 August 2006 11:11 AM
> > To: Year 12 Information Technology Systems Teachers' Mailing List
> > Subject: Re: [Year 12 Its] Ongoing misinformation about topology
> >
> > Frank's comments strike a chord with me.  I came into computer 
> > teaching without formal qualifications in the area, but having done 
> > programming
out
> > of personal interest for perhaps twenty years.  The whole networking 
> > and hardware side of things was not on my radar.  I have found the 
> > textbooks to be lacking in clarity and concision.  I don't mind my 
> > students knowing more about networking than I do, because some of 
> > them are acquiring that knowledge in very practical ways.  But other 
> > students who aren't attuned to hardware aspects, and I myself, could 
> > surely be served better by the textbooks we use.  When some time ago 
> > I asked my techie about some of the explanations offered, he thought 
> > they were pretty much irrelevant.
> >
> > Alex Hopkins
> >
> >
> > Quoting Frank Van Den Boom <vandenboomfj at aquinas.vic.edu.au>:
> >
> >>
> >>
> >> 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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Anton Yoxon
Learning Technologies Manager
yoxon.anton.w at edumail.vic.gov.au


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