Network Chapter2 - Network Component

8/9/2019 Network Chapter2 - Network Component

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Lesson 2:Network Components

This is the subtitle


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Objectives At the end of this session, you will be able to:

Understand the types of signal transmissiontechniques.

Distinguish between the different types of

cabling employed in a computer network.

List the characteristics and types of coaxial

cables. Configure the network adapter card


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Objectives(contd)

List the characteristics and types of twistedpair

List the characteristics of fiber-optic cables. Specify the type of cabling required for a

particular computer network.

List the types of wireless computernetworks.

Explain the requirement for a networkadapter card.


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Medium

Is the network component over which themessage is transmitted

Determines how fast is the network Determines the speed at which the network

works


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Network Cabling

Depending upon the cable most networks

are classified into: Coaxial

Twisted pair

Fiber-optics


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Coaxial Cables

Are the most popular network cable

Are inexpensive, light and flexible

Have a conducting wiresurrounded by Insulation

A braided metal shieldingthat:

acts as a shield

protects the core from crosstalk An outer covering that:

Are resistance to interference and attenuation

C i l bl h i i


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Coaxial cable showing variouslayers

Outer shield

Insulation (PVC, Teflon)

Conducting coreCopper wire mesh oraluminum sleeve



Attenuation causes signals to

deteriorate



Coaxial Cables (contd.)

Are classified into two kinds

Thin coaxial cables

Also referred to as the thinnet Are flexible

Can be directly connected to the networkadapter

Can carry a signal for a distance of about185m

Have an impedance of about 50 ohms

Belong to RG-58 family of cables



Close-up view of thinnet cable

showing where it connects to acomputer




Thick coaxial cables Also referred to as the thicknet or standard

Ethernet

Are relatively rigid

Is also referred to as Thicknet

Support data over large distances

Can be used to connect several smaller

thinnet-based networks

Can be connected to a thinnet coaxial by theuse of transceiver

Attenuation causes signals to deteriorate



Thicknet cable has a thicker core

than thinnet

Thicknet

Thinnet


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Are available in two grades

Polyvinyl Chloride (PVC)which is:

Used commonly Flexible

Inexpensive plastic used as insulation andcable jacketing

Plenum

Is certified to be fire resistant

Is more expensive than PVC

Is less flexible


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Plenum grade cabling is requiredby fire code in the plenum

Plenum grade cable

Plenumgrade cable

Polyvinylcholoride

Plenum grade cable


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British Naval Connections Are required by the coaxial cables to connect

the cable and the computer Have various components

BNC cable connector:

is either soldered or plugged BNC T connector:

joins the network interface card to the

network cable BNC barrel connector:

joins two separate thinnet cables

BNC terminator:

closes each end of the terminal


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BNC cable connector

BNC cable connector


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BNC T connector

BNC T connector


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BNC barrel connector

BNC barrel connector


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Jump to first page

BNC terminator

BNC terminatorGround lead


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Twisted-Pair Cables

Use two stranded wires that are twistedtogether

Are grouped together to form a cable

Are categorized on the bases of qualitygrading

Category 1

Refers to telephone cable

Can carry voice but not data

Category 2

Has four twisted pairs

Can carry data upto the rate of 4Mbps


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Twisted-Pair Cables (contd.)

Category 3


Can transmit data up to the rate of 10 Mbps

Category 4


Is certified for data transmission upto 16 Mbps

Category 5


Is certified for data transmission upto 100Mbps


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Twisted-Pair Cables (contd.)

Are of two kinds

Unshielded twisted-pair (UTP) Shielded twisted-pair (STP)


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Unshielded twisted-pair and

shieldedtwisted-pair cables

Shielding


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Unshielded Twisted-Pair (UTP)

Is commonly used in LAN cabling

Is also used in telephone lines Has a maximum cable length segment of

100 m

Is susceptible to cross talk


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UTP cable


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Shielded Twisted-Pair

Uses a copper braid

Has a foil wrap between and around the wirepairs for insulation

Is less susceptible to crosstalk

Supports higher transmission rate


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STP cable


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Crosstalk occurs when signals

from one line mix into anotherline


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Connectors

Are used to connect computers

Are also called RJ connectors Are of different types

RJ-11

houses four cable connections RJ 45

houses eight cable connections


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RJ-45 connector and jack

Various twisted pair cabling


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Various twisted-pair cablingcomponents

Expandable patch

panels

Distribution rack

and shelves

Wall plates

Jack couplers


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Fiber-Optic Cable

Transmits light signals instead of electrical

signals

Has an inner core of glass or plastic that:

Conducts lights

Is surrounded by cladding which reflectslight back into the core

Is a more efficient medium than othersbecause of its

Bandwidth capacity that: is very high

can allow data rates from 100Mbps to 2Gbps


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Fiber-optic cable

Fiber-optic connector

Optical fiber (core) Glass cladding

Protective outer sheath(jacket)


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Fiber-Optic Cable (contd.)

Attenuation is much lesser than in acopper wire

can carry the signal over largedistances

Electro Magnetic Interface (EMI) is

very secure does not allow cross talk

Si l T i i


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Signal Transmission

Is the way data is transmitted across a media

Is classified into:

Analog signals

change continuously with time Are represented as a wave cycle

information represents all the values in a range

Digital signals

information exists in discrete states: ON or OFF, 1or0

change instantaneously


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Signal Transmission (contd.)

Two transmission techniques are used for the

transmission of analog and digital signals

Baseband transmission

Uses digital signaling over a single frequency Has devices that transmits bidirectionally


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Baseband transmission showing

bidirectional digital wave


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Broadband transmissionshowing unidirectional analog

wave


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Signal Transmission (contd.)

The two ways of providing data flow are:

Mid-split broadband Divides the bandwidth into two channels

one to transmit and other to receive the signal

Dual-cable broadband Has each of its devices attached to two cables

one to send and the other to receive the signal


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Wireless Network

Has no cables

Relies on earths atmosphere to act as thetransmission medium

Is classified into:

Local area networks

Extended local area networks

Mobile computing


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Wireless Local Area Network

Has the same topology as a cabled LAN Has wireless components which connect the

different parts of the network

Wireless computers communicate with thecabled network with the use of transceivers

Transmission techniques include:

Infrared

laser

Narrow-band(single frequency) radio

Spread spectrum radio

I f d d L T h i


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Infrared and Laser Techniques

Infrared Technique

Reflective network

requires all computers to direct alltransmissions to a common location

Broadband optical telepoint can handle high quality multimedia

requirements

provides broadband servicesLaser Technique

Employs laser technology

Requires a direct line of sight unlike infrarednetworks


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Narrow Band Radio Technique

Requires the transmitter and the receiver to

tune to a single frequencySpread Spectrum Radio

Uses the same frequency as narrow band

radio Uses several frequencies simultaneously

unlike narrow band radio

Point-to-Point Transmission

Technology transfers data from one computerto another

Is different from communication that takes

place on a network


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Mobile Computing (contd.)Transmission is possible through: Packet-radio communication

Cellular networks

Microwave systems

Packet-Radio Communication

Involves the breaking of the data unitscalled packets

Broadcasts the data packets afteruplinking them to a satellite


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MicrowaveSystem

Is very effective in connecting buildings thatinvolve short distance communication

Consists of :

Two radio transceivers to receive andtransmit the broadcast

Two directional antennas to establishcommunication of the signals broadcast bythe transceivers

Network Adapter card


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Network Adapter card Acts as an interface between the computer and the

network cable Manages the flow of network information to and

from the computer in which it resides

Converts the data in a form that can travel over anetwork cable

Communicates with the receiving card prior totransmitting data over the network to determine

the:Maximum size of the data packet

Time interval between sending data packets

Speed of data transmission


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Network Card Adapter (contd.)

Has the following configuration options:

Interrupt requests (IRQ)

Base I/O port address

Base memory address

Network Adapter Card Must have the appropriate

type of cable connector and match with thebus architecture to ensure compatibilitybetween the computer and the network


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Interrupt Request (IRQ)

Is a request for service sent by the devices to theCPU

Lines transmit requests from the devices to the

CPU Network adapter cards commonly use IRQ 5

Base I/O Port Address

Specifies a channel for data flow between eachhardware device

Is generally free for use with the following LANadapters:

280h 300h 320h 360h


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Network Chapter2 - Network Component

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