Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!snorkelwacker.mit.edu!stanford.edu!leland.Stanford.EDU!Panther.Stanford.EDU!morgan
From: morgan@Panther.Stanford.EDU (RL "Bob" Morgan)
Newsgroups: comp.dcom.lans
Subject: Re: 10Base-T hubs
Message-ID: <1991Apr9.181721.15560@leland.Stanford.EDU>
Date: 9 Apr 91 18:17:21 GMT
References: <1548@vtserf.cc.vt.edu> <1991Apr08.171237.19978@shl.com> <1582@vtserf.cc.vt.edu>
Sender: news@leland.Stanford.EDU (Mr News)
Distribution: usa
Organization: Networking Systems, Stanford University
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Re 10Base-T:

>As others have pointed out, the cost savings aren't in physical
>capital costs - they are in people time saved from not having to
>fix and diagnose broken segments.

Hmm, my numbers show that 10Base-T is cheaper in almost every case
(excepting those special cases of student labs and such that benefit
from big-time daisy-chaining), even before the less immediate wins of
using the structured cabling, etc.

The cheapest thinnet MPR we've found has 9 ports (8 thin + 1 AUI) and
runs about $1300 = $162.50 per thinnet port.  The cheapest 10Base-T
MPR has 14 ports (12 T + 1 thin + 1 AUI) and they want to sell it to
us for the remarkable price of $700 = $58.33 per T port.  A $100 win
per port right off the bat.  Lest you think this is a fluke, there are
multiple vendors beating down our doors wanting to sell 10Base-T MPRs
for around $900/12 = $75/port.

Now cabling.  My rule of thumb for contractor-installed thinnet in
existing office space is about $100/office for quick & dirty, $150 for
nice-looking (ie all in wiremold, etc).  This isn't really affected
much by whether you daisy-chain or not, since most of the cost is in
the connectors and the time spent in the rooms and stringing the
cable, not in the cable itself.

Our on-campus telephone people, who support their operation entirely
by user fees, are willing to do the wiring part of installing 10Base-T
(ie, mounting punchblocks and cross-connects and labelling and any
futzing with the jack that might be required) for $50 per circuit plus
a $150 setup per job.  We also choose to use a 110 block with RJ-45s
mounted in it for jumpering to the MPR, which runs $100 or so.  BTW, I
haven't found an existing telephone circuit here yet that couldn't run
10Base-T acceptably (but then we haven't put in that many yet).

10Base-T Ethernet cards are only a few dollars more than thinnet these
days.  Jumper cables (wall outlet to computer) cost about the same for
the two methods.

So, comparing variable costs for an 8-station network (which puts
thinnet in the best light):

Thin:

Repeater:            $1300
Cable installation:    800
                      ----
                      2100
10Base-T:

Repeater:              700
Cable installation:    650
                      ----
                      1350

So 10Base-T wins already, not even considering that we have 4 ports
left over, we didn't have to get contractor bids, users didn't have to
get their offices disrupted, moves and changes are much easier, etc.

Even if all this weren't already compelling enough, an enormous win in
our situation is that our on-campus telephone people are prepared to
install these kinds of nets using their existing techs who already
know how to handle twisted pair cable.  This simply wasn't the case
for thinnet.  We're working out the procedures now so they can just
take the whole process and run with it.  So the *biggest* cost savings
of all (IMHO) is that these networks can be installed en masse by
readily-available, well-trained telephone people; you no longer need
to use hard-to-find, expensive computer-network types who'd rather
spend all their time sending news articles 8^).

I'd like to see the numbers of those who say thinnet is cheaper.
Again, I'll believe you if you're mostly installing student labs and
such, but here at least those are mostly done already.  The challenge
is giving network access to every single office on campus, and that's
where 10Base-T wins big.

 - RL "Bob" Morgan
   Networking Systems
   Stanford