Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!pacbell!belltec!lance
From: lance@belltec.UUCP (Lance Norskog)
Newsgroups: comp.dcom.lans
Subject: Re: Simple thin ethernet question
Summary: Thin Ethernet/Star networks
Message-ID: <384@belltec.UUCP>
Date: 31 Jul 89 17:15:47 GMT
References: <2946@ukecc.engr.uky.edu> <383@belltec.UUCP> <194@usna.MIL>
Distribution: usa
Organization: Bell Technologies, Fremont, CA
Lines: 25


Mr. Smith is absolutely right about star-shaped networks.  Star-shaped
networks are the easiest to maintain in the long run because all failures
can be chased down via a binary search method, usually at one location.
That is, you stand if fron of the rack, and play with plugs until you
have found the bad cable, instead of running around with a clipboard
building a large test log and trying to make sense of it.

This is why IBM's Token Ring, from the beginning, was wired physically 
as a star rather than daisy-chaining cables directly between computers.
(Possibly the only wise architectural decision in TR :-)

However, my point was that the BNC connectors on Thin Ethernet tend to
degrade when you flex the cables.  If you run them through walls you
should leave a long tail at each end so that you can keep chopping off bad
connectors and re-connectorizing them.  Thick Ethernet is better in this
regard, and also gives cleaner signal.   So, you should follow Mr. Smith's 
architectural plan but use Thick yellow cable instead of Thin black stuff.

Besides, with the yellow stuff nobody gets the bright idea of using 75ohm
video cables instead!

Lance Norskog
Sales Engineer
Streamlined Networks