Chapter 6: The Internet pptx

Ũ Chapter Contents * Section A: Internet Technology * Section B: Fixed Internet Access * Section C: Portable and Mobile Internet Access * Section D: Internet Services * Section E: I

NEW PERSPECTIVES COMPUTER CONCEPTS

Chapter 6

The Internet

Ũ Chapter Contents

* Section A: Internet Technology

* Section B: Fixed Internet Access

* Section C: Portable and Mobile Internet

Access

* Section D: Internet Services

* Section E: Internet Security

Background

* The ARPANET, created in

1969, connected computers at UCLA, Stanford Research

Institute, University of Utah, and University of California at

santa Barbara

and supplies information to

people of all ages and interests

* With an estimated 200 million

nodes and 1 billion users, the Internet is huge

Internet Infrastructure

* The Internet is not owned or operated by any single

corporation or government

* The Internet backbone is a network of high-capacity

communications links that provides the main routes for data traffic across the Internet

* Backbone links and routers are maintained by

network service providers (NSPs}

* NSP equipment and links are tied together by

network access points (NAPs)

* An Internet service provider (ISP) is a company that

offers Internet access to individuals, businesses,

and smaller ISPs

Internet Infrastructure

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Internet Infrastructure

* To communicate with an ISP, your computer

uses some type of communications device,

such as a modem

UDP User Datagram Protocol

HTTP Hypertext Transfer Protocol

FTP File Transfer Protocol

POP Post Office Protocol

SMTP Simple Mail Transfer Protocol

VoIP Voice over Internet Protocol

IRC Internet Relay Chat

BitTorrent BitTorrent

Function Creates connections and exchanges packets of data Provides devices with unique addresses

An altemative data transport to TCP used for DNS, Voice over IP, and file sharing

Exchanges information over the Web Transfers files between local and remote host computers

Transfers mail from an e-mail server to a client Inbox

Transfers e-mail messages from client computers to an e-mail server

Transmits voice conversations over the Intemet Transmits text messages in real time between online users Distributes files using scattered clients rather than a server

Internet Protocols,

Addresses, and Domains

* A domain name is a key component of Web

addresses, e-mail addresses, and addresses

on the Web called URLs

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Internet Protocols,

Addresses, and Domains

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The first step in registering a

domain name its to find out

whether the name is currently

in use or reserved for future use If a domain name ts not available, consider using a

different top-level domain,

such as biz instead of com

After you’ve found an

available domain name, you

can continue the registration process by filling out a simple

online form

Ũ Connection Speed

* Data travels over the Internet at an incredible

speed

*The elapsed time for data to make a round

trio from point A to point B and back to point

Connection Speed

* When upstream speeds differ from downstream

speeds, you have an asymmetric Internet

connection

* When upstream and downstream speeds are the

same, you have a symmetric Internet connection

* Internet connection options

— Fixed Internet access

— Portable Internet access

— Mobile Internet access

* DSL, and Dedicated Lines

* Cable Internet Service

* Satellite Internet Service

* Fixed Wireless Service

* Fixed Internet Connection Roundup

Dial-up Connections

* A dial-up connection is a fixed Internet

connection that uses a voiceband modem

and telephone lines to transport data between your computer and your ISP

To the Internet

Your computer Telephone

and modem wall jack

Dial-up Connections

* A voiceband modem converts the signals

from your computer into signals that can

travel over telephone lines

* Modem speed is measured in bits per second

D Digital signal a"

Ũ DSL, ISDN, and

Dedicated Lines

*T1, T3, and T4 lines are leased from the

telephone company, and offer fast, high-

capacity data transmission

DSL, and

Dedicated Lines

*DSL is a high-speed, digital, always-on

Internet access technology that runs over

— Most DSL installations require

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computer's USB or Ethernet port

Ũ Cable Internet Service

* Cable Internet service distributes always-on

broadband Internet access over the same infrastructure that offers cable television

Ũ Cable Internet Service

* Cable modems convert your computer’s

Signal into one that can travel over the CATV

network

* Always-on connection

Ũ Satellite Internet Service

* Satellite Internet service distributes always-

on, high-speed asymmetric Internet access

by broadcasting signals to and from a

personal satellite dish

* A satellite modem is a device that modulates

data signals from a computer into a

frequency band that can be carried to the

satellite dish where It is converted to another frequency, amplified, and transmitted

Downstream

speed (actual) Latency Short video (72 MB) download

Requirements

Monthly fee

Installation cost

Always-on

56 Kbps

33 Kbps

44 Kbps 100-200

ms

4 hours

Telephone line, ISP, voiceband modem

128 Kbps

128 Kbps

10-30

ms

78 minutes

Telephone line, ISDN service, ISDN terminal adapter

ms

5 minutes

Computer

located within

3 miles of local telephone switch; DSL modem

3 Mbps 10-20

ms 3.2 minutes

400 Kbps 1—3 seconds

24 minutes

Clear view

of southern sky; satellite dish and modem

70 Mbps 1.5-3 Mbps 10-50

ms 6.4 minutes

* Portable and Mobile WiMAX

* Portable Satellite Service

* Cellular Data Service

Chapter 6: The Internet

Wi-Fi Hotspots

A Wi-Fi hotspot is an area

In which the public can

access a Wi-Fi network that

offers Internet service

Wi-Fi does not typically

provide acceptable mobile Internet access because you can only remain

connected within range of

the network's hotspot

Cellular Data Services

* Using cellular phone technology to access

the Internet offers mobility that is not yet

possible with most of today’s wired or wireless computer network technologies

Service Speed

Analog voice service

ao ==- all No data service

Digital voice service

TDMA, and GSM netwo rks UTMS 2 Mbps

EDGE 384 Kbps Superior digital voice service 3G Broadband multimedia data

EV-DO 24M services HSUPA 5.76 Mbps

* Maximum theoretical speed; actual speeds are slower

Cellular Data Services

* The fastest cellular technologies

for Internet access are EDGE,

EV-DO, and HSUPA

* Most cellular service providers

offer a data service plan for

accessing the Internet

* You can use a cellular-ready

PDA, such as Palm Treo,

Blackberry, HP iPAQ, or Dell

Axim to directly access the

Real-Time Messaging

* A networked-based real-time messaging

system allows people to exchange short

messages while they are online

— Instant messaging (IM)

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Voice over IP

* VoIP (Voice over Internet

Protocol) or Voice over IP, cbie//

is a technology in which a

connection is used to place uJ

telephone calls instead of

the regular phone system

* To set up a standard VoIP

system, you can use an Ye | vitedireless

inexpensive ATA, IP phone, ~~ ư

wireless IP phone, or USB

— Quality can vary

— Must have power to work

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File Sharing

* P2P file sharing uses peer-

to-peer (P2P) protocols that

allow users to obtain files

from other users located

anywhere on the Internet

* BitTorrent is a file sharing

protocol that distributes the role of file server across a collection of dispersed

Destination

* Routers and NAT

* Virtual Private Networks

Chapter 6: The Internet

Intrusion Attempts

* An intrusion is any access to data or programs

by hackers, criminals, or other unauthorized

persons

* Looking for open ports is one of the most

common ways of gaining unauthorized access to

a network-based computer

* A port probe (or port scan) uses automated

software to locate computers that have open

ports and are vulnerable to unauthorized access

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Securing Ports

* One of the easiest

steps to enhance your

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Ũ Routers

* Routers are intended to work on LANs to

monitor and direct packets being transported

from one device to another

* A routable IP address is one which can be

accessed by packets on the Internet

* A private IP address is a non-routable IP

address that can be used within a LAN, but

not for Internet data transport

Virtua Private Networks

* It is possible to secure remote connections

by setting up virtual private network (VPN)

access to a remote access server in the

corporate office

* Access to a VPN is usually by invitation only

Employees who need to access a VPN are

given the necessary instructions, addresses,

and passwords to make connections

Virtual Private Networks

Virtual Private Network

NEW PERSPECTIVES COMPUTER CONCEPTS

Chapter 6 Complete

The Internet