Cohousing-L Mailing List: Re: Common House Technology Cost Savings

[R.P. Aditya (aditya]

Hi Robert,

On Sun, Apr 08, 2007 at 09:31:12PM -0400, Robert Heinich wrote:
> In order to take advantage of shared internet cost, where does one begin to
> investigate installing conduits and network wiring for an existing community.

on cohousing-L of course! At Great Oak Cohousing in Ann Arbor, Michigan, we
have an Ethernet network covering all units on our campus. Just for the record
we use a Comcast commercial cable modem line (6Mbps down, 768K up for
$80/month) and for backup have a TDS business DSL line ($150/month includes 5
business phone lines we use for the Common House plus offices therein). We
have been experimenting with a "mesh"-wireless network from www.meraki.net in
addition to the wired infrastructure, and will likely have blanket wireless
later this summer. We charge $10/month per opt-in household, and 30 out of 37
households have chosen to use it (the others either don't have it, use dialup,
or have their own directly from Comcast).

> For those interested in our topology, here is the google map of Eno Commons:
> http://www.google.com/maps?q=1+Indigo+Creek+Trail,+Durham,+North+Carolina+27712,+USA&sa=X&oi=map&ct=title
>
> Fortunately, all houses seemed to be within 300 feet of the Common House.

Our campus looks to be about the same topology as yours, maybe a bit more
compact -- we have a star topology with half the runs entering one end of the
common house and the other half entering on the other end.

http://www.gocoho.org/campus/

We also have a "networking closet", picture at
http://www.gocoho.org/campus/common_house/ (at the bottom left of the page)
that all the runs are punched-down on a block and then connected into a switch
on a UPS.

> Does anyone have a ball park figure on the cost of installation?  Also what
> post installation concerns should I look into?

Our network was installed during construction -- no conduit was laid, instead
we used "direct bury" cable, about 1 foot in the ground, that a local
electrical contracter recommended. 3+ years later, it seems to work pretty
well, except for a few places where it was nicked during construction or
subsequent digging. For the runs we've had cuts in, we had to take the step of
having it rerun, and to that end did what is described here:

  http://gocoho.org/blog/?p=20

with photos showing the conduit and the minimally invasive conduit laying:

  http://gophotos.fluidthoughts.com/main.php?g2_itemId=1363

What we plan to run in that conduit is direct bury cable (for additional water
protection):

  http://www.cat5ecableguy.com/inc/sdetail/12770

that has a ground wire. One of the main problems with installing copper cable
is that it conducts electricity so if you have any lighting strikes close by,
it can fry electronics at either end of a run, as we have had a couple of
times (though now that the family with an ungrounded PV array has moved away
it hasn't happend :-) Of course, since all the buildings on a campus are
typically not grounded to the same thing, you risk other interesting grounding
effects if it weren't for the low-voltage use of the cat5 cable!

In any case, lots detail about why you don't want to run copper for network
between buildings on a campus from some of my colleagues who think about this
for a living:

  http://www.merit.edu/mail.archives/nanog/2005-09/msg00492.html

So based on that discussion, plus the fact that we don't have conduit and
running optical fiber between buildings, though cheap, would require expensive
electronics on either end that we can't afford, we decided to use cat5
lighting protectors in each unit -- both the Trippe-Lite DNET1 and the APC
PNET1 (now called PNET1GB) serve the same purpose -- and a switch with
replaceable modules (in case a hit fried some modules) in the Common House --
the HP Procurve 4000m we bought on eBay with some 8-port 10/100 modules.

Hope that helps,
Adi