Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!unmvax!polyslo!rnicovic
From: rnicovic@polyslo.CalPoly.EDU (Ralph Nicovich)
Newsgroups: comp.dcom.lans
Subject: Re: Thin ethernet questions
Message-ID: <9890@polyslo.CalPoly.EDU>
Date: 29 Mar 89 21:33:50 GMT
References: <724@m3.mfci.UUCP>
Reply-To: rnicovic@polyslo.CalPoly.EDU (Ralph Nicovich)
Organization: Cal Poly State University -- San Luis Obispo
Lines: 47

Tan,
I read your posting to USENET about your building wiring, and I have
a few sugestions. Without knowing more about the problem some of my
sugestions may be inapropriate.
I have just finished working on a network interconnecting some 85
buildings on a major university and have come by many of the problems
you are mentioning.
First off you may be selling short the capacities of a single(logical)
ethernet it seems to me that you have a lot of networks tied to a
backbone, you may not need so many. Another thing is that unless
there are some major security concerns I would not worry to much
about a user being on the propper network, just plug him in the
network that is in the office, let the software find his propper
resources.
About the thinnet. In my opinion Thinnet is not ment to connect
large groups of workstations. Although it has the same capabilities
as far as bandwidth, the number of connections and the mechanical
reliability of it, makes it less than ideal. With repeaters such
as the CABLETRON MR9000C you can expand it but watch out for NOISE
problems and to many levels of repeaters. There is no neat way you can
set it up as you wish. The specs allow for 30 taps into the cable.
Normaly this would be 30 "T" connectors. In my opinion if you "looped"
thru an office the way you described each one would count as 3
connections. Also any person unplugging one of these cables would
totaly bring down the network.
I would treat the network and the wiring as two seperate resources.
The networks will change as time goes by, the wiring should be done once.
I would personaly wire the building with the AT&T PDS system.
This entails RJ-45 jacks in the offices that "home-run" to the nearest
WIRE CLOSET. I would put 2 jacks in each office, One to be used
by the telephone people and the second for data. The one for the
telephone could allow for up to 4 telephones. The one for data could
support token-ring, 3270, rs232, ethernet etc...
The only place that equipment should be is in the wire closet.
Look at Ungermann-bass Access-One, at HP Starlan (10MBs version) and
Cabletron. You may pay a premium on capitol equipment to start with
but it will add years to your life if you have a reliable system
that works. Moves and changes will be simple with patch cords.	
When you think about it the workstations you are connecting , if
they use ethernet, are not cheap to begin with. Why make the network
out of a kluge that will drasticaly effect the performance ,and
usability of these same workstations?
Ralph Nicovich
Network Engineer
Cal Poly State University, SLO
(805)-756-1297
rnicovic@polyslo.calpoly.edu