Installing a Physical Network. Chapter 8

Installing a Physical Network

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

Structured Cabling

• Structured cabling is a set of standards for cable installers to follow

Cable Basics

• All new network technologies use UTP and a

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

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

Horizontal Cabling

• Cabling from the PCs to the equipment room is

called horizontal cabling

• A single piece of horizontal cabling is called run

Work Area

• The work area is simply the office where the PC is located

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

Horizontal Cabling Details

• EIA/TIA specifies horizontal cabling use a solid

core

• Cable installers recommend the highest grade

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

Choosing Horizontal Cabling

• Most network people use only CAT 5e or CAT 6

today

• Network installers may try to install a lower

Equipment Room

• All horizontal runs come together in the

equipment room

• EIA/TIA’s structured cabling standards define

Equipment Racks

• Equipment is mounted

into equipment racks…a central component of the equipment room

– 19 inches wide but vary

Rack Mountable Equipment

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

• 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

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

Work Area Issues

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?

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

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

Equipment Room Issues

• Coolness

– Equipment rooms get warm; make sure there is an air

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

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

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

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

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

Connecting the Patch Panels

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

Labeling

patch panels

Labels on the patch panel and

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

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)?

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

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

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

Switches

• A network with three switches installed instead

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 segments

High-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

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

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

Token Ring NICs

• Token Ring NICs use

either the older and rarer female DB-9 connector or the newer RJ-45

Know Your NICs

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

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

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

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

Activity Lights and More

• The activity light on a NIC will flicker when there is network activity

• Multispeed NICS may also contain speed 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

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

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

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

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