11

NetworksNetworks

The Great Information Exchange

The Great Information Exchange

22

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

33

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

44

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

55

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.

66

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

77

Network ComponentsNetwork Components

• Transmission media

• Network adapters

• Navigation devices

• Network software

• Transmission media

• Network adapters

• Navigation devices

• Network software

88

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

99

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

1010

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

1111

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

1313

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

1414

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

1515

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

1616

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

1717

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

1919

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)

2121

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

2222

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

2323

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

2424

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

2525

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

2626

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