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Networking

Define what a network means

List the basic components of a data communication system

Explain the different types of network configurations or topologies

CHAPTER 7

Objectives:

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Communications

Process in which two or more computers transfers data, instructions, and information

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Communication

What is needed for successful communications?

Sending device — initiates

instruction to transmit data,

instructions, or information

Receiving device — accepts

transmission of data, instructions, or

information

Communications channel — media

on which data, instructions, or

information travel

Communication Device Communication Device

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Communication

Communication Device

Sending Device Receiving Device

Communication channels

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Networks

Network is a collection of computers and devices connected by communication channels

To facilitate communications, share hardware, data and information, software, etc

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TYPES OF NETWORKS:

LOCAL AREA NETWORK (LAN)

METROPOLITAN AREA NETWORK (MAN)

WIDE AREA NETWORK (WAN)

Networks

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Type of Networks

1. Local Area Network (LAN) Privately owned communication network Home, school computer laboratory or office

building

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2. Metropolitan Area Network (MAN)

Network that covers geographical area

Connects LANs in city or state

Type of Networks

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3. Wide Area Network (WAN)

Network that covers large geographical area - country.

Consists of 2 or more LANs/MANs

Internet is world’s largest WAN

communications satellite

Type of Networks

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How data travel ?

Analog Signal is a continuous electrical signal in the form of a wave and it is called as a carrier wave. Frequency – how many times it completes a

cycle in a second Amplitude – the height of a wave within

a given period of time

Volts Analog Signal5

0

-5

(sec)

2 complete cycles in 1 sec.

Frequency = 1Hz, Amplitude = 10v

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Digital signal consists of individual electrical pulses that represent bits grouped together into bytes.

On/off - present/absentOn/off - present/absent electrical pulses in electrical pulses in discontinuous wavediscontinuous wave

Represents 0s/1s. ( two state binary language)Represents 0s/1s. ( two state binary language)

How data travel ?

0

5

(sec) 1 1 0 1 1 0 1 0

Volts Digital Signal

2 states On - 5v - 1 and OFF - 0v – 0

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Communication Devices

Function of a communications devices Capable to transmit data, instruction and information

between sending and receiving devices.

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Example of communications devices

Common types are dial-up modems, ISDN and DSL modems, cable modems, wireless modems, network cards, wireless access

points, routers, and hubs


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Modem (Modulate/demodulate)

Transmission speed speed at which modem transmit data measurement - bits per second (bps) or kilobits

per second (kbps)

Computers use digital signal and some communication channel uses analog signals.

Convert digital signal to an analog signal and vice versa

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MODULATION DEMODULATION

MODEM

To convert a digital signal into an analog signal

To convert an analog signal into

a digital signal

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Type of Modem External Modem Internal Modem PC Card Modem Wireless Modem


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Network cards Adapter card, PC Card or flash card that enables a computer or device to access network.

called network interface card (NIC)

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Communication DevicesWireless Access Point

Allows computers and devices to transfer data wirelessly among themselves or wirelessly to a wired network.

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Router

connects multiple computers and transmits packet of data to its correct destination.

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Communication Channels

Bandwidth amount of data that

can travel over a communications

channel

Transmission media on which data, instructions or information travel in a communication system

Type of transmission media

Physical

Wireless

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Wire, cable and other tangible materials used to send communications signals

Physical transmission media

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Twisted - Pair cable the wires are twisted together to reduce “noise” -

electrical disturbance suitable for short distances used for telephone systems and network cabling


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Coaxial cable produce high quality transmission often used for cable television wiring advantages:

less affected by electrical interference “noise”



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Fiber optics cable Consist thin strand of glass send data

through light beams Advantages:

carry more data signals faster data transmission less affected by “noise” smaller size

Disadvantages: more expensive difficult to install and modify



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Used when inconvenient, impractical, or impossible to install cables

Wireless transmission media


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Infrared Sends signal using infrared

light waves. Suitable for short distances Mobile devices such as

handphone, notebook and PDA.



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Broadcast Radio distributes radio signal

through the air over some distance.

It need transmitter (send signal) and receiver

E.g: Bluetooth, HomeRF, Wi-Fi technology



Cellular Radio Form of broadcast

radio – mobile communication

Transmit voice and digital data messages

Categories of cellular transmission : 1G, 2G, 3G

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Microwave transmission used radio waves

that provide a high-speed signal transmission

Line-of-sight transmission



Microwave station

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Satellite transmission Space stations send and

receive signals from earth-based stations .

Geosynchronous orbit - the place that allows the satellite to remain positioned over the same spot on earth



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Dial up lines Temporary connection using telephone line

for communications (need to reestablish the connection )

Modem has to convert digital data into analog signal before it can travel through the telephone network.

Communication Over the Telephone Line

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ISDN lines Digital transmission of data over standard

copper telephone line Needs ISDN modem Advantages:

data transmission speed is faster than dial-up modem

the ISDN circuit has two phone lines to connect to the Internet to talk on the phone


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T-Carrier Lines Digital telephone line that carry multiple

signals over a signal communication channel.

Provides very fast data transfer rates. Used by large companies - expensive T1 - Most popular T-carrier line


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ADSL Digital telephone line for small business and

home user. Can transmit at fast speed An example of this service is the streamyx

connection provide by TM bhd. user who subscribed to this line need to

have an ADSL modem.


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LAN

Network Topologies Configuration, or physical arrangement, of devices in a

communications network Networks usually use combinations of three topologies

bus ring star

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Bus network All computers and devices connect to central

cable or bus Inexpensive and easy to install

LAN - Network Topologies

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Ring network Cable forms closed

ring, or loop, with all computers and devices arranged along ring

Data travels from device to device around entire ring,in one direction


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Star network

All devices connect to a central computer, called the hub

All data transferred from one computer to another passes through hub

HUB

printer


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LAN - Network Communication Standard Specific combinations of hardware and software

that allow different devices on several types of networks to communicate or connected

Ethernet Token Ring

TCP/IP Wi-Fi

Bluetooth

IrDa

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Ethernet

LAN technology that allows personal computers to contend for access to network

Based on bus/ star technology

personal computer

personal computer

personal computer

personal computer

personal computer

LAN - Network Communication Standard

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Token Ring

Technology controls access to network by requiring devices to pass a special signal,

called token

Only device with token can transmit data over

network at a time


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TCP/IP

Define how data should travel through the Internet data is sent to the right destination.

Transmits data by breaking it up into small pieces packets

Packets Data divided into small

pieces

TCP Breaks the message into

data packets and reassembles them once reach their destination.

IP Assign each packet a unique

address.


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Wi-Fi

Define how data should travel through the wireless network

Hot spots

provide users to connect to the internet wirelessly with their

wireless mobile devices


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Bluetootho Define how two

Bluetooth devices use short range radio waves to transmit data

o Bluetooth devices contains small chip to allow it to communicate.


IrDao Define how data is

transmitted via infrared light waves

o Line-of-sight transmission

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Connection and cabling system Use either wire / wireless transmission.

Computer with NIC Networking OS Bridge

a combination of hardware and software that recognizes the messages on a network and passes on to the receiving nodes in another network.

To connect similar network..

LAN - Component

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Router Gateway

Allows a node to communicate with another node on a dissimilar network (eg : Star to Ethernet)

LAN - Component

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The design of computers, devices and media in a network. LAN network categories:

Client/Server Peer-to-Peer Internet peer-to-peer

LAN - ARCHITECTURE

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Client/server Server – 1 or more computer that controls the network Client – other computers that can request services from

the server

client client client

serverlaser printer

LAN - ARCHITECTURE

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Peer-to-peer Small network that

shares hardware, data or information located on any computer in the network

Each computer is called peer

printer may be used by all computers on

network

printer may be used by all computers on

network

network operating system and

application software installed on each

computer

network operating system and

application software installed on each

computer

LAN - ARCHITECTURE

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Characteristics of peer-2-peer.

Each computer on the network communicate directly with one another without relying on server.

Each computer has same status, responsibilities, and capabilities.

Simple, inexpensive, suitable for very small businesses and home users.

Disadvantages – lack of speed

LAN - ARCHITECTURE

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Internet peer-to-peer (P2P)

Enables users to exchange file directly from the hard disk over the Internet

Criteria :1. use compatible

software 2. connected to the

Internet

LAN - ARCHITECTURE

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INTERNET Internet is worldwide collection of networks that

links millions of computers together allows all of the computers to communicate with

one another

E-mail Information Shopping Meeting people Entertainment

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INTERNET

ISP

home user

THE INTERNET

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INTERNET PROTOCOLInternet Protocol (IP) – language that computers use to communicate

over the Internet

http://www.mmu.edu.my/~fosee/staff/jun.html

Protocol Domain Name

Path File Name

IP Address- Unique identifying number- E.g. 10.0.48.50, 209.11.168.133, 74.125.19.99,

209.131.36.158

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