[K12OSN] Networking a new school for K12LTSP?

Wed Jan 24 23:15:05 UTC 2007

1) Just for clarification: Gigabit speeds can be attained over fiber
optic media as well as electrical.  There are also different
specifications depending on the type of media that you use.

But in general, when you hear a "gigabit backbone" mentioned, the idea
is that you have at least 1 gigabit per second between your intermediary
distribution frames (IDFs) and your main distribution frame (MDF).

If you can get away with it, like I mentioned in an earlier response,
try to have all of your cables terminated in one networking closet and
you can purchase a single, larger switch rather than multiple edge type
switches.  However, this is only a viable solution if all of your
horizontal cable runs are less than 90 meters.

2) You can have solid Category 6 cable or stranded.  Solid cable has
superior electrical characteristics.  Stranded cables are more flexible,
easier to work with, and can be moved around quite a bit more without
breaking the wires inside as easily.

3) In the case of a managed network, the fewer switches the better.  Not
only does it make administration easier, but you have fewer pieces of
hardware that can fail.  Throw into the mix that by having switches in
the classroom you run the risk of student sticking pencils in the fans
and unplugging the power to the switches all day long.  I would know...
unfortunately we still have a school wired with several hubs in the
fashion until E-rate pulls through and we can re-wire :)

4) Also ask them to see what kind of boxes they have for the floors and
walls.  I can't recall the manufacturer, but we have some really nice
floor boxes which open up so that you can plug in all of your power and
Ethernet cables horizontally, and then you can close the tops with the
cables poking out through a slot similar to the one shown here:

http://www.tlc-direct.co.uk/Images/Products/size_3/UVCSM3SLASH4.JPG

5) I might have a different opinion on this than Steven :)

You can run gigabit ethernet over Category 5, 5e, 6, and 7 cabling up to
a distance of 100 meters (or so).  So 100 feet will be no problem at
all.  I would suggest running 2 cables between the MDF and your IDF for
redundancy (you may want to read up on spanning tree protocol).

Category 6 and 7 cabling will also support 10 gigabit Ethernet (amended
in IEEE 802.3an).

(If the building is being constructed now, you can have them lay conduit
which is of sufficient size so that you can have more copper pulled down
the road or even have some fiber blown.)

6) Absolutely

7) And make sure the labeling isn't cheap!  We always have contractors
try to slap some cheap stickers on which fall off in just a matter of
days due to heat and/or humidity.

8) Definitely worth mentioning to the contractors, although they should
be well aware of this.  But if this is your first construction project,
heed this advice: STAY ON TOP OF EVERYTHING.  Trust no one!  Make sure
the right number of cables get pulled, make sure the cabling is up to
spec (no sub-standard crap), make sure the drops are where you want
them, etc.

You're going to be paying them a whole lotta money, so you'd best get
what you want :)

-Abe

-----Original Message-----
From: k12osn-bounces at redhat.com [mailto:k12osn-bounces at redhat.com] On
Behalf Of Joseph Bishay
Sent: Wednesday, January 24, 2007 12:10 PM
To: Support list for open source software in schools.
Subject: Re: [K12OSN] Networking a new school for K12LTSP?

Hello,

I hope you are doing well.  Thank you all for the responses -- I've
learned a LOT about this topic.

I'm going to be meeting with the electrical people in order to discuss
this further.  I've gone through the various emails and some small
questions have arisen

1) Gigabit backbone -- is that just cat6 cabling or does this relate
to topology?  And if topology, what kind is the best for LTSP?

2) What is the difference between solid wires and regular cat 6?  Is
there a name for this specification?

3) Is it always the case that it's better to have a room with 4 drops
for 4 computers, rather than 1 drop and a switch for the 4 computers
to plug into?

4) I really like the idea of floor drops and power outlets where the
network drops are -- thanks!

5) We're going to, due to the distances involved, have a primary
server room where the network cables terminate, and a secondary room
as well.  Is it necessary to connect them via fiber? The distance
between them is probably 100 feet.  I'm asking because the hardware to
convert fiber <-> copper is rather expensive.  Is it not easier to run
several cat6 and somehow bridge them? (technical details fuzzy, but I
think you know what I mean! :) )

6) For wiring wireless -- this may be something we do in the future?
Can I ask them to run cables and power to specific spots in the
ceiling and then just leave it as is?

7) Labeling each of the cables with numbers/room location with
validation - I got it!

8) How much of an issue are florescent lights?  Our building is filled
with them -- should I make a point to mention this?

I look forward to your responses!

Joseph

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