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RE: Network cabling

Just some notes from my head about the CABLING part.

Structured cabling:
  general, flexible network for many types of traffic (data/tele/...,
  all (end) equipment has same connection to network
    (like RJ45 connector)
  simple administration
  easy to prepare outlets for all workspaces
  easy to service and solving problem
  easy to document
  high production quality

I divide the network into tree nets:
  campus net, ie. between buildings
  backbone? net, between floors or parts of a building
  access net, between backbone access points (wiring closets) and the
    end equipment (like a pc)

Cables I use are usually halogen-free stp cat 5 cable for the access
net. Cable length "in the wall" <= 90m, leaving 10m for patch cables.

And same cat 5 cable type or single mode fiber for the backbone/campus
net depending on need.

If you like, you can make redundant paths from access hubs/switches to
distribution switches/routers, and elsewhere, like Cisco recommends
(you might get info at cisco web site).

Induced noises and such (90% of disturbance is from within a building):
  place cable ~ 1m/kV from potential disturbance source
    like 25cm from a common 240V unshielded power line (>=2kVA load), utf cable
    like 5cm   - " -             shielded power line (<2kVA load), stf cable
  some sources are worse, like railroad and some medical equipment
  note, the cable screen is of less use against 50-60Hz noises
  divide building in protection zones
  ALL cables and pipes (like water pipes) must be "guarded" at the zone border
    with eg. gas discharge tubes and/or varistors
  possible use lightning conductor
  use good ground lines (like 25/32 mm2 or bigger) to a good ground sink/source
  avoid vertical metal loops
    high voltage is most easily induced by lightning that way
    note the metal loop can be part network cable, power cable, water pipe
  avoid any metal loops in the building, build like a flat star/floor

Installation notes:
  be gentle with the cable
    don't squeeze it
    don't bend it with a to small radius
  since that might give you points with impedance change which results
    in signal reflextions, ie. possible useless link
  in cable to connector/panel connection (cat5), untwist cable at most 13mm
  connect RJ45 outlet as in:
    1  orange/white
    2  orange
    3  green/white
    4  blue
    5  blue/white
    6  green
    7  brown/white
    8  brown
  Basically 1 (in the outlet) goes to 1 (in the panel),
    and the cable pairs are use pins 1/2, 3/6, 4/5, 7/8
  Above pinout is called EIA/TIA 568B and is used everywhere except in
    the other end of a crossed cable (which connects as 1-3, 2-6, 3-1,
    4-4, 5-5, 6-2, 7-7, 8-8)
  Rent a cable tester to verify installation, connecting to the wrong
    pin is not uncommon when you do a lot of them

Usual design:

  one wiring closet per floor containign access hubs/switches
  from here cables go out in a star fashion to wall outlets forming the
  access net

  the wiring closets are connected to the buildings "main" closet
  where the distributon switches/routers are
  this distribution net is also in star fashion (cable wise) with the
  main closet in the center

  for some demands you can have a second "main closet" with its own
  distribution net to the access switches as a backup
  this is "more to configure" tough

  thoose "main closets" of each building are connected to a "core"
  closet to connect buildings with eachother

I.e. a tree design of three levels of star nets with possible redundant


Karl Hammar                    Aspö Data           karl@kalle.csb.ki.se
Lilla Aspö 2340             +46  173 140 57                    Networks
S-742 94 Östhammar         +46  10 270 26 67                  Computers
Sweden                                                       Consulting

From: "Antropov Anton" <dicobraz@mail.ru>
Subject: RE: Network cabling
Date: Mon, 12 Nov 2001 12:43:31 +0500

> It is necessary to know more details.
> What speeds?
> What architecture?
> What distances?
> Etc...
> > -----Original Message-----
> > From: Szabo Tamas [mailto:sztamas@ots.rdscj.ro]
> > Sent: Monday, November 12, 2001 12:06 PM
> > To: debian-firewall@lists.debian.org
> > Subject: Network cabling
> > 
> > 
> > Hi!
> > 
> > Sorry if it's too offtopic, but I think it's a little related to the
> > list.
> > Please just ignore if not interested.
> > Thanks for understanding...
> > 
> > I need to do some network cabling. The problem is that I never did
> > cabling for more then 20 PC's. This will be more then 50 and the network
> > should extend between several buildings so I'm a little frightened. I
> > could order a book but I'm in a big hurry so I have no time to wait for
> > it.
> > 
> > Can someone please point me to some online documentation? Something
> > about structured cabling design...
> > 
> > Or can someone answer to some basic questions in private(to not bother
> > the list further with this...)?
> > 
> > Waiting for any help
> > Thanks,
> > Tamas

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