installing a physical network...contents •recognize and describe the function of basic components...
TRANSCRIPT
Installing a Physical Network
Chapter 8
Contents
• Recognize and describe the function of basic
components in a structured cabling system
• Explain the process of installing structured
cable
• Install a network interface card
• Perform basic troubleshooting on a structured
cable network
Structured Cabling
Network Diagrams
Structured Cabling
• Structured cabling is a set of standards for cable
installers to follow
• Defined by EIA/TIA
Cable Basics
• All new network technologies use UTP and a
physical star topology
The Basic Star
• There’s nothing preventing you from placing a
hub in the middle of the office and running
cables across the floor to all the PCs. But it does
present issues in the real world
– Cables can be tripped over
– Cables can be damaged from stepping on them
– Interference may be present
– Limits your ability to make changes or to troubleshoot
Structured Cable Network
Components
• Structured cabling requires
– An equipment room
– Horizontal cabling
– Work area
Equipment Room
• Cables run from the work area to a central
equipment room
Equipment Room
Horizontal Cabling
• Cabling from the PCs to the equipment room is
called horizontal cabling
• A single piece of horizontal cabling is called run
Horizontal cabling
Work Area
• The work area is simply the office where the PC
is located
Work area
Horizontal Cabling Details
• Usually CAT 5e or better UTP cable
• UTP cable has either a solid or stranded core
– Solid core conducts better but is stiffer and breaks
easier
Stranded
coreSolid
core
Horizontal Cabling Details
• EIA/TIA specifies horizontal cabling use a solid
core
• Cable installers recommend the highest grade
cable you can afford using four pairs
Fire Ratings
• When a building catches on fire the insulation
on cables that burns could cause noxious fumes
and smoke
• Underwriter’s Laboratories and the National
Electrical Code have developed fire ratings
– Poly-Vinyl Chloride (PVC) creates smoke and noxious
fumes when burned
– Plenum-rated cable creates much less smoke and
fumes
• Most city ordinances require the use of plenum-rated cable
Choosing Horizontal Cabling
• Most network people use only CAT 5e or CAT 6
today
• Network installers may try to install a lower
grade, so specify CAT 5e or CAT 6
Equipment Room
• All horizontal runs come together in the
equipment room
• EIA/TIA’s structured cabling standards define
special components in the equipment room
Equipment Racks
• Equipment is mounted
into equipment racks…a
central component of the
equipment room
– 19 inches wide but vary
in height
Rack Mountable Equipment
• Hubs
• Switches
• Servers
• Uninterruptible
Power Supplies
(UPSs)
Rack
mounted
UPS
Patch Panels and Cables
• A patch panel is simply a box with a row of
female connectors (ports) in the front and
permanent connections in the back to which you
connect horizontal cables
• Patch panels allow you to organize your cables
Patch Panels
• Label your patch panels so you can locate
where the cables go
• UTP, STP, or fiber ports
• 8, 12, 24, 48 or more
ports
• UTP comes with CAT
ratings
Patch Cables
• Once the horizontal cabling is run and connected to the back of the patch panel, you use patch cables to connect to hubs or switches
• Patch cables are short 2 to 5 foot straight-through UTP cables using a stranded wire core
Equipment Room
• Equipment rooms may be
dedicated rooms, or part of a
storage room, or a specially-
made cabinet with built-in
equipment racks
Work Area
• The work area
manifests itself in the
wall outlet where
horizontal cabling is
terminated
• The wall outlet is a
female jack where you
would connect your PC
using a patch cable
Wall Outlet
• Female RJ-45 jack
should have the same
CAT rating as your
cabling
• It is a good idea to label
your wall outlet to
identify the position on
the patch panel in the
closet where the cable
goes
Distances
• The horizontal cable may be at most 90 meters
in length according to the EIA/TIA 568
specification
• The patch cable in the closet may be up to 6
meters in length
• The patch cable in the work area may be up to 3
meters in length
• Add it up…99 meters or about 100 meters (the
maximum for UTP)
Work Area Issues
• Most network failures occur in the work area
Planning the Installation
• Professional installers assess your site and plan
your installation in detail before a single piece of
cable is pulled
– Can you stay within the 90 meter distance limit?
– How will you route the cable?
– What path should you take to the wall outlets?
Floor Plan
• Installers should always begin with a floor plan
– Shows the locations of potential closets, firewalls, and
so forth
• If you don’t have a floor plan, create one by
poking around the ceilings, closets, and
locations of rooms
Map the Runs
• A cable drop is the location where the cable
comes out of the wall
• Map out where the cables will be run
• Talk to users and management about current
and future needs
• The typical price for a network installation is
around $150 per drop
Inside or Outside the Walls
• Do you want to run your cables inside or outside
the walls
• Raceways adhere to the outside of the walls and
make sense in some older buildings
Equipment Room Issues
• Distance
– Choose an equipment room location that is centrally
located to keep maximum runs to 90 meters
• Power
– Generally put your equipment room outlets on their
own dedicated circuit
• Dryness
– Choose a dry room with low humidity
Equipment Room Issues
• Coolness
– Equipment rooms get warm; make sure there is an air
conditioning duct in the room
Equipment Room Issues
• Access
– Prevent unauthorized access – the room should be
locked
– Make it easy to get to the equipment to maintain and
troubleshoot it An equipment
room that has
become a
broom closet –
not good!
A server
wedged in the
back of a closet
and hard to get
to – not good!
Equipment Room Issues
• Expandability
– Will your equipment room be able to grow to
accommodate a growing network?
– If another closet needs to be located in the next floor
up, how easily can it be accessed from the current
closet?
Equipment Racks
• Equipment racks
– Most equipment rooms use a floor-mounted
equipment rack
– A smaller network may be able to use a wall-mounted
short rack or just a wall-mounted patch panel
Installing the Cable
• Pulling cable requires two
people to get the job done
quickly
• Most pullers start from the
equipment room
• Cable is drawn from a reel
• Professional cable pullers
have many interesting
tools to get the job done
Pulling Cable
• Old cable installations did not follow any
standards…leaving a mess
• Good cable management is important and must
adhere today to local codes, EIA/TIA, and the
National Electrical Code (NEC) rules
• Proper hooks and cable trays should be used
Pulling Cable
• Running the cable down through the wall to an
outlet on the wall takes skill
– A hole is cut in the drywall using a stud finder
– A weight on the end of a nylon string is dropped
through the wall down to the opening
– The network cable is tied to the nylon rope and
then pulled down
Pulling Cable through
the Wall
– An outlet box or low-voltage mounting bracket is then
installed in the wall
– The cable is then terminated on the back of the jack
– A faceplate covers the front of the mounting bracket
Equipment Room Cables
• Many cables coming from work areas must be
consolidated in the equipment room
• Special cable guides will help to bring the cables
down to the equipment rack
Making Connections
• The cable then needs to be connected at both
ends
– On the jack in the work area
– On the back of the patch panel in the closet
– The cables should be documented and labeled
– Every connection should be tested
Connecting the Work Area
Attaching a
jack to a
wire
Fitting the
jack into a
faceplate
Tool used
to make a
110-
punchdown
- the most
common
Connecting the Patch Panels
• It is important to use proper cable management
in the closet
• Plastic D-rings guide patch cables neatly along
the sides and front of the patch panel
• Finger boxes are used to run individual cables
Connecting the Patch Panels
Poor cable
manage-
ment
Good
cable
manage-
ment
Connecting the Patch Panels
• Organize the patch panel based on your network
– Either based on the physical layout of the network
– Or based on user groups
Labeling the Cable
• EIA/TIA defined the 606 labeling scheme
• Design a labeling scheme that matches your
network’s organization
• Label the outlet in the work area and the jack on
the patch panel with the same number
• Color coding may be desirable
Labeling
Well organized
patch panels
Labels on the
patch panel and
outlet match
Testing Cable Runs
• Professional cable installers run advanced tests
on the cabling
– For example, near-end crosstalk and attenuation-to-
crosstalk ratio
• Most network administrators and technicians
only do minor testing with simple cable testers
Testing Cable Runs
• How long is the cable?
• Are any of the wires broken?
• If there is a break, where is it?
• Are any of the wires shorted together?
• An any of the wires in the wrong order (split or
crossed pairs)?
• Is there electrical or radio interference?
Simple Cable Testers
• Simple cable testers cost
under $100 and only test
for breaks in the wire by
testing continuity
Time Domain Reflectometer
• A medium priced cable
tester (around $400+) can
determine the length of
the cable and where a
break is located
• Called a Time Domain
Reflectometer (TDR)
Advanced Cable Testers
• Advanced cable testers cost over $1000
– Tests the electrical characteristics of the cable
– May generate a printed report
– May draw a diagram of the network including MAC addresses, IP addresses, and even operating systems for each computer
– Called media certifier tools
Beyond the Basic Star
Adding Hubs
• The network may be expanded by adding
additional hubs that are then connected together
– As more nodes are added to the network traffic
increases
– Hubs will extend the size of the collision domain
– Network performance will suffer
Switched Networks
• Hubs send the frames received on one port out
all the other ports
• Switches send a frame received on one port only
out the destination port – conserving lots of
bandwidth
• Hubs may simply be replaced with switches to
greatly increase performance
Hubs and Switches
• Switches used to be far
more expensive than
hubs, but today they are
about the same price
• Switches have become
the standard network
appliance – replacing
hubs
• Switches and hubs look
alikeOne is a hub – one is a switch
Switches
• A network with three switches installed instead
of hubs
Multispeed Networks
• Faster technology isn’t always the best
– It costs more and rewiring may be necessary
– The increased speed may not be needed
• Multispeed switches have some ports that run at
one speed and others that run at a higher speed
• Some switches have all ports that may run at
different speeds – the ports are autodetecting
and will sense what speed they need to run
Multispeed Switches
• Segments with servers attached or segments
that connect with other parts of the network
(called the backbone) may need higher speeds
than other segmentsHigh-speed ports
Multispeed ports
lit up on a switch
Multiple Floors & Buildings
• Generally, networks use one equipment room
per floor provided the cabling runs do not
exceed the 90 meter limit
• If an office uses more than one floor, then you’ll
have multiple networks on multiple floors
• Backbone segments tie the networks together
• Larger networks require more servers, which are
often grouped together in a single computer
room
EIA/TIA Standards
• EIA/TIA 568 standards address cabling configuration and performance specifications
• EIA/TIA 569 standards address cable pathways and installation areas involving multiple equipment rooms, floors, and buildings– Equipment room
– Horizontal cabling
– Work areas
– Backbone
– Building entrance
– Telecommunications closets
Backbones
• When a network is split into multiple floors or buildings, they are interconnected with high-speed backbone segments
• EIA/TIA recommends UTP or fiber optic for backbone segments
– Backbone cabling is called vertical cabling or risers
– Fiber optic cabling is recommended between buildings
Building Entrances
• The building entrance is where all the cables
from the outside come into a building
– Telephone lines
– Cables from other
buildings
NICs
NICs
• Network Interface Cards (NICs) are a common
component in PCs today
• They are used to connect to a network
• A NIC needs to meet three criteria
– Technology such as Ethernet, Token Ring, or FDDI
– Speed such as 10 Mbps, 100 Mbps, or 1000 Mbps
– Type of bus such as ISA or PCI
Ethernet NICs – 10Base5
• 10Base5, or Thicknet,
NICs use a female, 15-
pin DB connector
– Called Digital-Intel-
Xerox (DIX) connector
• Drop cable runs from
the DIX connector on
the NIC to the
Attachment Unit
Interface (AUI) or
transceiver
Ethernet NICs – 10Base2
• 10Base2 or Thinnet
NICs use a BNC
connector that
attaches via a T-
connector
Ethernet NICs – 10BaseT
• 10BaseT, 100BaseT,
and Gigabit Ethernet
NICs all use RJ-45
connectors
• The cable runs from
the NIC to a hub or
switch
Ethernet NICs – Fiber Optic
• Fiber optic NICs use
either SC or ST
connections
– An ST connector is
shown in the figure
Token Ring NICs
• Token Ring NICs use
either the older and
rarer female DB-9
connector or the
newer RJ-45
connector
Know Your NICs
• How do you know if a NIC is
Ethernet or Token Ring if they
both have RJ-45 connectors?
• What speed does the NIC run
at?
• What software driver do I
use?
• These questions can be
answered by finding the
model number which is
usually printed on the card
somewhere, or you should
label it in the beginning
Installing NICs
• Installing a NIC involves 3 steps
1. Physically install the card in the PC
2. Assign unused system resources to the NIC using
Plug and Play or manually
3. Install the proper drivers
Buying NICs
• It’s better to stick with the name brands like
3Com or Intel
• Multispeed cards are usually better
• Try to stick with the same model
– Many companies standardize on which NICs to buy
Physical Connections
• Physically inserting the NIC into the PC is straight forward
• Make sure the NIC is for the proper expansion slot type
– The most common is Peripheral Component Interconnect (PCI)
– PCI-X is a faster slot used for Gigabit Ethernet NICs
– USB connections may be used but are slower
– PCMCIA or PC Card connections are seen on laptops
PCI
USB
Drivers
• Most NICs are plug and play and install easier in
Windows systems
• However, Windows will most likely choose its
own driver that is outdated
• It is better to install the driver that came with the
NIC, and even better to download and install the
latest driver off the Internet
Link Lights
• Most NICs have lights (really Light Emitting
Diodes or LEDs)
• A link light tells you the NIC is connected to a
hub or switch
– There’s also a light on the hub or switch
Activity Lights and More
• The activity light on a NIC will flicker when there
is network activity
• Multispeed NICS may also contain speed lights
• Older NICs may contain collision lights
Fiber Optic NICs
• Fiber optic NICS rarely have lights
• Most problems are traced to the ST or SC
connection on the NIC
• An optical tester will allow you to test the
connections
Direct Cable Connections
• Recent versions of Windows include software
that enables direct serial-to-serial, parallel-to-
parallel, or infrared-to-infrared port connections
– Serial port connections require a null-modem cable
– Parallel port connections use a IEEE 1284-rated bi-
directional parallel cable
• These connections are only good to connect two
PCs together
Diagnostics and Repair of Physical
Cabling
Diagnosing Physical Problems
• Most network problems are layer 1, or Physical
layer, issues
• These manifest themselves as a device not
showing up in My Network Places or “server not
found” errors
• However, if you can do one network task (such
as browse the Internet) but can’t do another (like
check e-mail), then it is a software issue
Check Your Lights
• Check your link lights – if they are not on then
you have a cable issue
– A bad connection or maybe the wall outlet is bad or
turned off at the closet
– The System Tray icon may indicate “Network cable
unplugged”
– The horizontal cabling may be at fault
– If other users in the area also have a problem, then the
issue may be the switch or hub
Check the NIC
• A bad NIC could also cause a problem with
network connection
– Verify the NIC is working in Device Manager
– Run the NIC’s diagnostic software if available
– A loopback test sends data out of the NIC to see if it
comes back
Cable Testing
• Horizontal cable may be tested with a mid-range
tester with TDR
• If the horizontal cable is bad, then it is best to
replace the entire cable
Toner
• If cables aren’t properly labeled, then they may
need to be traced
• Use a toner to trace cables
– Uses a tone generator that connects to the cable and
sends an electrical signal along the wire
– A tone probe makes a sound when placed near the
right cable at the
other end
– Toners are rather
inexpensive
– Sometimes called by
the brand name
Fox and Hound