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