11 Networks The Great Information Exchange. 2 Networking Fundamentals Computer network: Two or more computers connected together Each is a Node Benefits.

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NetworksNetworks

The Great Information Exchange

The Great Information Exchange

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Networking FundamentalsNetworking Fundamentals• Computer network:

• Two or more computers connected together• Each is a Node

• Benefits of a network:• Sharing resources• Transferring files

• Computer network:• Two or more computers connected together

• Each is a Node

• Benefits of a network:• Sharing resources• Transferring files

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Network ArchitectureNetwork Architecture

• Network designs:• Individual PC controlled:

• Peer-to-peer (P2P)

• Centrally controlled:• Client/server

• Network designs:• Individual PC controlled:

• Peer-to-peer (P2P)

• Centrally controlled:• Client/server

Peer-to-peer

Client/server

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Peer-to-Peer NetworksPeer-to-Peer Networks

• Nodes communicate with each other:• Peers

• Share peripheral devices:• Printers• Scanners

• Home and small office networks

• Nodes communicate with each other:• Peers

• Share peripheral devices:• Printers• Scanners

• Home and small office networks

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Client/Server NetworksClient/Server Networks

• Client computers:• Users

• Server computers:• Provide resources to clients• Central network control

• Internet• A large, multi-server, multi-client network.

• Client computers:• Users

• Server computers:• Provide resources to clients• Central network control

• Internet• A large, multi-server, multi-client network.

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LANs and WANsLANs and WANs

• Local area network (LAN):• Nodes are within a small geographic

region:• Homes• Schools• Small businesses

• Wide area network (WAN):• LANs connected over long distances:

• A few miles to thousands of miles• Use telecommunications lines

• Local area network (LAN):• Nodes are within a small geographic

region:• Homes• Schools• Small businesses

• Wide area network (WAN):• LANs connected over long distances:

• A few miles to thousands of miles• Use telecommunications lines

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Network ComponentsNetwork Components

• Transmission media

• Network adapters

• Navigation devices

• Network software

• Transmission media

• Network adapters

• Navigation devices

• Network software

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Transmission MediaTransmission Media• Provides communications channel

between nodes• Forms of media:

• Telephone wire:• Twisted pair

• Coaxial cable• Fiber-optic cable• Radio waves:

• Wireless

• Bandwidth:• Data transfer rate• Throughput

• Provides communications channel between nodes

• Forms of media:• Telephone wire:

• Twisted pair• Coaxial cable• Fiber-optic cable• Radio waves:

• Wireless

• Bandwidth:• Data transfer rate• Throughput

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Network AdaptersNetwork Adapters• Devices connected to or installed in

nodes:• Network interface cards (NIC)• External network adapter

• Enable communication between nodes

• Devices connected to or installed in nodes:• Network interface cards (NIC)• External network adapter

• Enable communication between nodes

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Network Navigation Devices

Network Navigation Devices

• Devices that help make data flow possible

• Routers:• Route data between

networks

• Switches:• Receive data and

retransmit it to nodes on the network

• Devices that help make data flow possible

• Routers:• Route data between

networks

• Switches:• Receive data and

retransmit it to nodes on the network

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Networking SoftwareNetworking Software• Peer-to-peer Software:

• Built into operating systems that support networking

• Windows• Mac OS

• Client/server Software • Network operating system (NOS) software

• Windows XP Professional• Windows Server 2003• Novell Netware

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Ethernet NetworksEthernet Networks• Ethernet network

adapters are used to connect nodes• NIC card• PC Card• USB adapter

• Computers are connected to each other using unshielded twisted pair cable

• Ethernet network adapters are used to connect nodes• NIC card• PC Card• USB adapter

• Computers are connected to each other using unshielded twisted pair cable

RJ-45

Phoneline

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Ethernet SwitchesEthernet Switches

• Keep track of data packets• Amplify and retransmit signals• Keep the network running

efficiently

• Keep track of data packets• Amplify and retransmit signals• Keep the network running

efficiently

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Ethernet RoutersEthernet Routers• Transfer packets from one network to

another• Home Internet routers transfer data from the

Internet to the home network.

• Transfer packets from one network to another

• Home Internet routers transfer data from the Internet to the home network.

Router

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Wireless NetworksWireless Networks• Use radio waves to connect nodes• Basically an Ethernet network that uses radio

waves instead of wires• Each node requires a wireless network

adapter:• Transceiver

• Use radio waves to connect nodes• Basically an Ethernet network that uses radio

waves instead of wires• Each node requires a wireless network

adapter:• Transceiver

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The Internet: The BasicsThe Internet: The Basics

• Origin of the Internet• The Web vs. the Internet• Clients and servers• Connecting to the Internet

• Origin of the Internet• The Web vs. the Internet• Clients and servers• Connecting to the Internet

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The Origin of the InternetThe Origin of the Internet• ARPANET:

• Advanced Research Projects Agency Network• Funded by the US Government in the 1960s• Allowed computers at leading universities and research

organizations to communicate with each other over great distances

• ARPANET:• Advanced Research Projects Agency Network• Funded by the US Government in the 1960s• Allowed computers at leading universities and research

organizations to communicate with each other over great distances

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The Internet vs. The Web The Internet vs. The Web • Internet – part of the system

that is primarily hardware infrastructure (telecommunications, routers, servers, disk drives, etcetera)

• Web - part of the system that contains intellectual property in many multimedia formats (test files, graphic files, sound files, video files, etcetera)

• Internet – part of the system that is primarily hardware infrastructure (telecommunications, routers, servers, disk drives, etcetera)

• Web - part of the system that contains intellectual property in many multimedia formats (test files, graphic files, sound files, video files, etcetera)

INTERNET

WWW

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Client and ServerClient and Server• Client computer:

• Users connect to the Internet• Request data and Web pages

• Server computers• Store Web pages and data• Return the requested data to the client

• Client computer:• Users connect to the Internet• Request data and Web pages

• Server computers• Store Web pages and data• Return the requested data to the client

Server

Client

2020

Connecting to the InternetConnecting to the Internet• Dial-up connections:

• Uses standard telephone line

• Least costly connection• Requires a modem

• Converts analog and digital signals

• Slowest connection speed (56kbps)

• Dial-up connections:• Uses standard

telephone line• Least costly connection• Requires a modem

• Converts analog and digital signals

• Slowest connection speed (56kbps)

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Broadband ConnectionsBroadband Connections

• Digital Subscriber Lines• Faster than dial-up

• Upstream (16Kbps -640kbps)• Downstream (1.5 Mbps – 9

Mbps)

• Requires special DSL modem

• Digital Subscriber Lines• Faster than dial-up

• Upstream (16Kbps -640kbps)• Downstream (1.5 Mbps – 9

Mbps)

• Requires special DSL modem

DSL modem

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Broadband ConnectionsBroadband Connections• Cable:

• Uses TV coaxial cable• Fast connection speed

(300kbps – 4mbps)• Speed depends on

number of users• Not available in all

areas• Requires a cable

modem

• Cable:• Uses TV coaxial cable• Fast connection speed

(300kbps – 4mbps)• Speed depends on

number of users• Not available in all

areas• Requires a cable

modemCoaxial cable

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Satellite ConnectionsSatellite Connections

• Uses a satellite dish and coaxial cable• Download speed

500kbps• Upload speed

100kbps• Signal is affected

by location and weather

• Uses a satellite dish and coaxial cable• Download speed

500kbps• Upload speed

100kbps• Signal is affected

by location and weather

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Comparing Internet Connection Options

Comparing Internet Connection Options

Connection Option

Maximum Upload Data Transfer Rate (approximate)

Maximum Download Data Transfer Rate (approximate)

Dial-Up 56kbps 56kbps

DSL (ADSL)

300 kbps 1 Mbps

DSL (SDSL)

1.5mbps 1.5mbps

Cable 500 kbps 6 mbps

Satellite 100kbps 400kbps

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Internet Service ProvidersInternet Service Providers• ISP:

• Internet service provider• Provide user access to the

Internet• National, regional or local

companies

• ISP:• Internet service provider• Provide user access to the

Internet• National, regional or local

companies

• OSP:• Online service provider• Provide online proprietary

content as well as Internet access

• AOL, CompuServe, MSN

• OSP:• Online service provider• Provide online proprietary

content as well as Internet access

• AOL, CompuServe, MSN

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Choosing an ISPChoosing an ISP

• Factors to consider:• Customer service• Local access numbers• E-mail options • Cost• Trial period

• Factors to consider:• Customer service• Local access numbers• E-mail options • Cost• Trial period