Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!samsung!munnari.oz.au!brolga!bunyip.cc.uq.oz.au!kirk!bambi
From: bambi@kirk.nmg.bu.oz.au (David J. Hughes)
Newsgroups: comp.dcom.lans
Subject: Re: how to connect thin wire segements to thick wire backbone
Message-ID: <3021@kirk.nmg.bu.oz.au>
Date: 14 May 91 05:05:33 GMT
References: <1991May13.170657.4786@zoo.toronto.edu>
Organization: Communications Development & Operation, Bond Uni, Australia
Lines: 56



From article <1991May13.170657.4786@zoo.toronto.edu>, by henry@zoo.toronto.edu (Henry Spencer):
> The only way to connect thin to thick is end to end.  You can't connect
> a thinwire segment to the middle of a thickwire segment.  Ethernet cable
> is a bus, not a tree -- it can't branch.  The only way to hook cables
> together at other than their ends is with a repeater of some flavor.


Correct yet not correct.  The overall structure of the Ethernet must be
a bus, but there are ways of introducing "stars" grafted onto the bus.
The set-up we use here is ...........



      |   _      Thin       Thin       _   |
      |  | |======             =======| |  |
Thick |::| |======             =======| |::| Thick
Spine |  |_|======             =======|_|  | Spine
      |                                    |
      |                                    |
      |               Router               |
       \                __                 /
         \_____________|  |_______________/
                       |__|
                        | 
		________|__________
               (___________________)
 		     Fibre Ring     \
                                      \  To another building


The Star configuration is maintained by a Multi-Port repeater (we use
3Com / Bridge).  This setup is repeated in every building on campus and
there is a pair of multi-repeater on every floor of every building.

To answer the original question, Yes you can do it this way but you will
be up for the $A4,000 per multi-port as I have not come accross any 2 or
4 port boxes.

> The simplest way to do what you want is to forget the central thick segment
> entirely and run the ends of the thin segments to a single multiport
> repeater at some central point.

This does not help if you are using the thick to overcome a distance
problem  (Hence the approx 10 KM of fibre in our setup.)


Bambi
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| David J. Hughes   (AKA bambi)	 |   bambi@kirk.bu.oz.au                     |
| Senior Systems Programmer	 |   bambi@kirk.bu.oz.au@uunet.uu.net        |
| Comms Development & Operations |   ..!uunet!munnari!kirk.bu.oz.au!bambi    |
| Bond University, Gold Coast    |   Phone : +61 75 951450                   |
| Queensland,  Australia  4229   |   Fax :   +61 75 951456                   |
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