the internetkitt/courses/412827/internet.pdf · 412 827: selected issues in information systems and...

1412 827: Selected Issues in Information Systems and Technology – The Internet

The Internet


Why do we need computer networks ?


(cont'd.) People need to communicate to each other.

Communication is a process to exchange information. Talk, read, write, gesture, act, ... Why we communicate ?

A computer is a machine to produce information. Some of its tasks cannot solely be done by a single computer. So, computers must communicate to each other too. We want to exchange information, not to change

information. Remember when you played “relay messages” game ?

How ? First ,let's see how we describe communication.


Dimensions of Communications Contents Forms Senders Receivers Dialogs Channels


Telecommunication Networks ? Édouard Estaunié, a french engineer,

coined this word in 1904. Tele- (Greek: τηλε) = far off Communicare (Latin) = to share


(cont'd.) In ancient times, this may be smoke signals,

drums, flags, ... In modern times, this involves the use of

electronic transceivers. One of its definition is the following:

“A set of devices, mechanisms, and procedures by which end-user equipment attached to the network can exchange meaningful information.”


(cont'd.) Now think about its dimensions :

How can we identify members in a network ? How can we convert information into bits ? How can we convert bits into signals ? What kinds of channels do we use ? How can we transmit and receive signals ? How can we establish a conversation ? How can we interact ? How can we overcome deficiencies ? ...

That's what we're going to learn, using the Internet as a model.


What is the Internet ?


(cont'd.) The Internet is “a network of networks”.

Interconnected sets of networks worldwide so that computers in those network could exchange information.

~1.73 billion users (~25.6% of population)

AsiaEuropeNorth AmericaLatin AmericaAfricaMiddle EastOceanea

Source: internetworldstats.com September 2009


(cont'd.)

KKUKKUgoogle.comgoogle.com


(cont'd.) ~500 M hosts

© 2005 The opte project


(cont'd.) Tier-1

If there exists the Internet backbone, it's tier-1. Directly connect to each of the other tier-1 ISPs Connect a large number of tier-2 ISPs AT&T, Global Crossing, Level 3, NTT (Verio) , Qwest,

Sprint, Tata (Teleglobe), Savvis, TeliaSonera, Verizon (MCI/UUNET)

Tier-2 Regional / national coverage Customer of tier-1 ISPs True Internet, TT&T, CS Loxinfo, TOT, CAT, SBN

(AIS), ...


Domestic Internet Exchanges

Source: http://internet.nectec.or.th/


International Internet Gateway

Source: http://internet.nectec.or.th/


Domestic Bandwidth

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 20100

100000

200000

300000

400000

500000

600000

700000

Band

wi d

th (M

b ps)

Current: 2010-01-01Bandwidth:641317 Mbps


International Bandwidth

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 20100

20000

40000

60000

80000

100000

120000

Band

wi d

th (M

b ps)

Current: 2010-01-01Bandwidth: 110,243 Mbps


Thailand Internet Users

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 20080

2000000

4000000

6000000

8000000

10000000

12000000

14000000

16000000

18000000

Use

rs ( #

)

Year 2008 ~ 16.1 M


(cont'd.) Because it is a network of networks ...

How can we transmit data across different kinds of networks ?

How can we find paths from a computer in one network to one another ?

Can I send my data through those networks ? Is it safe to send my data through those networks ? etc. etc. etc.


Layered Architecture Data communication is very complicated!

So, the software is complicated! Layered architecture divides the problem into

smaller functions. Each protocol belongs to one of the layer. Protocol on layer-n of a device communicates to the

others through messages called layer-n protocol data unit (n-PDU).

Layer n – 1 defines services provided to layer n. Layer n relies on layer n – 1 to deliver its n-PDU. Services defined in each layer are independent.


(cont'd.)Sender

Receiver


(cont'd.)

H1H1

Source Destination

Communication Channel

H2H2

H2H2

H3H3

H3H3

H3H3

MessageMessage

MessageMessage

MessageMessage

MessageMessage H1H1

H2H2

H2H2

H3H3

H3H3

H3H3

MessageMessage

MessageMessage

MessageMessage

MessageMessage


(cont'd.)

“Hello World!”……

48 65 6c 6c 6f 20 57 6f 72 6c 64 21 ...

48 65 6c 6c 6f 20 57 6f 72 6c 64 21 ...


(cont'd.)

1

2 3


Open System Interconnection Reference model for data communication 7 layers

Application LayerApplication Layer

Presentation LayerPresentation Layer

Session LayerSession Layer

Transport LayerTransport Layer

Network LayerNetwork Layer

Data-Link LayerData-Link Layer

Physical LayerPhysical Layer


(cont'd.)

DataData

H7H7

H6H6

H5H5

H4H4

H3H3

H2H2

PDUPDU

PDUPDU

PDUPDU

PDUPDU

BitsBits

T2T2

Med

ia L

ayer

sH

ost L

a yer

s

DataData

PDUPDU


Basic Terms Devices that connect to the network are called

“hosts” or “end systems”. Computers, PDAs, TVs, Mobile Phones, Cars,

Microwave Ovens, Photo Frames, etc. Sometimes end systems are divided into “clients”

and “servers”. In software context, there is another definition, a

“client program” and a “server program”. This client/server Internet application are

“distributed applications”.


(cont'd.) End systems are connected by “communication

links”. Copper wires, Fiber optics, Radio spectrum,

Particles, etc. Usually, end systems are not connected directly

but (logically) through intermediate switching devices called “routers”.

End systems transmit a chunk of information called a “packet” across networks.

All end systems, routers, and other components of the Internet run “protocols” that control how packets are handled.


Protocols A protocol defines the format and the order of

messages exchanged between two or more communicating entities, as well as the actions taken on the transmission and/or receipt of a message or other event.

Important protocols of the Internet: Internet Protocol (IP) Transmission Control Protocol (TCP) User Datagram Protocol (UDP)


TCP/IP Layer Architecture

IPIP

Data LinkData Link

PhysicalPhysical

IPIP

Data LinkData Link

PhysicalPhysical

ApplicationApplication ApplicationApplication

Source Destination

Router RouterTCPTCP UDPUDP

IPIP

Data LinkData Link

PhysicalPhysical

TCPTCP UDPUDP

IPIP

Data LinkData Link

PhysicalPhysical


IP on Everything The Internet Protocol is capable to operate on

any data-link layer. Currently, the data-link protocol used are:

IEEE 802.3 Ethernet IEEE 802.11 Wireless LAN (Wi-Fi) Point-to-Point Protocol (PPP) Asynchronous Transfer Mode (ATM) …


Applications on the Internet Client/Server Model

Web File Transfer E-mail – the first killer app on the net Remote Login Chat

Peer-to-Peer Model Virtually, any transport and application protocols

could be operated on the Internet Protocol. - Everything on IP.


World Wide Web Invented by Timothy

Berners-Lee at CERN around 1989 – 1990.

First web site was on-line on 6 Aug 1991.

Basically, it is a system to share web objects (HTML pages, images, …) by putting them on web servers Hyperlinks and URLs Web Browsers


Web Explosion Before the web, it was the gopher - text-based

contents (as files) through multilevel menus. Then, in 1993, NCSA developed the first

graphical web browser – Mosaic It's the ancestor of Netscape Navigator. This allows users to access the web easily.

Notable sites: 1991: CERN, WWW Virtual Library, SLAC 1992: NCSA, Fermi Lab, SunSITE 1993: MIT, MTV 1994: HotWired (Wired magazine), Lycos, Pizza Hut,

White House, Yahoo!


(cont'd.) 1995 – 1996: traded companies started to use

web. Initially, as a worldwide information publishing. Then, with two-way communication and electronics

payment, it led to e-commerce.

Order

VISA/Bank

Payment

Paid

Delivery


(cont'd.) 1998 – 2000: “Dot-com” Boom

Internet-related companies started their businesses. The worldwide information publishing is the key to

convince that the business has very high potential. Venture capitals invested on those companies. Stock market started to bubble, especially in the IT

sector. NASDAQ peaked on March 10, 2000.

Then, the market started to realize the reality. They were not always profitable. .. and the bubble popped.

Nonetheless, the “dot-com” boom attracts users to the web and the Internet.


(cont'd) 2001 - present: Web is everywhere.

After the dot-com busted, telecom companies started to loss their profits.

They lowered their charges, led to cheaper Internet accesses.

This attracted more users to be on-line. Not only companies, but home, and public areas.

Some companies emerged and were profitable because their quality of products and services.

On-line auction: e-bay Direct sells: Dell, Gateway, Amazon, … On-line ticketing: airlines, … ...


Search Engines With so many information available on the web, it

became quite difficult to manually find pieces of information you really wanted.

Early search engines and directories Lycos Altavista HotBot Yahoo! …

Most of them are freely available. So, how could those search engine companies do their business ?


(cont'd.) Technically, the engine crawls through the web

via the hyperlinks, gets web pages and creates keywords database.

A user visits the search engine web page, put a keyword to search, then the engine returns links to web pages that the keyword has been found.

With more accurate results, the search engine companies could attracts more users. So, the company could sell ads.


(cont'd.)

“Keyword”

Result: http://...http://...

DB


Google Search Engine

Actually, the founders – Larry Page and Sergey Brin – did not intend to create a search engine.

They have developed the PageRank. It's an algorithm to score a web page based on

keywords and number of links to the page.


(cont'd.) It turned out that the PageRank could provide

quite accurate search results. So, the engine attracts many users, and again

they could sell ads. Google shows ads based on the keyword.

Moreover, Google allows traded companies to bid for the keywords – this is called AdWords The more you bid, the higher rank your product would

popped on top of the ads. And you pay only when a user click on the link to your

products The AdWords service is the main source of Google's

revenue ~ $USD 21 billion in 2008


Web 2.0 Previously, companies created web sites to take

benefits from the web. It's a company-to-client communication.

Internet users may exchange information via personal web pages, and web boards.

Still creating a web page means a user must Understand HTML, or is capable to use web

development tools. Acquire a space on a web server to put the web

pages. Using web board is easier, just post whatever

they want, but it is not really personal.


(cont'd.) Web logs or blogs allow users to create their own

web pages via web interface. Hosted on a web server or a farm of servers.

The key is that blogs enable ad-hoc user-to-user communication. Contents on the Web (or the Internet) can be created

by individuals Democratize the web – contents no longer bound to

companies, organizations, … Blog posts are chronological contents – like diary or

journal New web era – the Web 2.0


(cont'd.) Example:


(cont'd.) Blogs could also be

Photographs (photoblogs) Videos Musics Audios (podcast) Links (e.g., digg)


(cont'd.) Blogs usually define relationships via hyperlinks,

feed aggregations, comments, ... Blogs are usually owned by individuals, so the

relationships are somewhat related to actual human relationships.

Companies, medias, universities, and other organizations also publish blogs Activities, events, courses, etc. Easier to communicate with their clients Marketing, CRM, ...


(cont'd.) Then, there is a newer kind of blog – microblog.

It's a blog but smaller/shorter messages. To express short moments, emerging thoughts, or

just “what I'm doing right now”. Allow to post messages using mobile devices

Now, users could post messages everywhere. Messages posted may include geolocation.


Impacts of the Internet

“Honey, I think the world is flat!”

The World Is FlatThomas L. Friedman


(cont'd.) With the Internet, most of the countries in the

world are less than one second away. And so the information

Search engines enable users to seek for information needed.

Shift from traditional to digital/on-line Research Education Commerce Public services Media ...


Research The Internet has significantly contributed to the

ease of research Communications Reference databases Academic publications Sending/receiving research

materials Up-to-date information ...


Education The Internet is the source of knowledge

Life-long learning It is also the infrastructure for

e-learning e-library Virtual classroom Virtual labs Class communication ...


Commerce On-line stores are everywhere on the Internet

$US 146 billion in the US in 2006 On-line payment

Credit/debit cards Electronic money, e.g., paypal Wire transfer

Taxation on e-commerce On-line stock trading e-Auction On-line taxation On-line advertising


Medias Shift from traditional to digital

News, books, magazines are all digital All news media companies are on-line. Quick/cheap delivery

Two-way communication Feedback from audiences


Games Game industries also take advantages from

world-wide connectivities of the Internet. On-line gambling may be the first

Availabilities of digital subscriber line (DSL) and cable modem allow users to get much higher bandwidth downstream to devices. From 56kbps analog MODEM to 256 kbps ADSL Currently, 2 Mbps ADSL is very common.

On-line games evolved to a massively multiplayer forms First wave to hit Thailand may be an MMORPG

named Ragnarok Online.


(cont'd.)

Member/subscription model In 2008, western consumers spend $US 1.4

billion on MMOG subscriptions. As off Dec 2008, WoW had > 11.5 million subscribers


Cloud Computing “Everything-as-a-service” on the Internet. Infrastructure

Amazon Web Services – provide virtual servers, unique IP addresses, blocks of storage on demand from API

Platform Software and development tools

hosted on the provider's servers e.g., Google App Engine provides

APIs to create web applicationson Google servers


(cont'd.) Software

Provider allows its customers to use its applications Users interact with the application through a use

interface (usually, web interface). Office suites Web-based mail Web chat Web conference

Client could be very thin. Netbooks Mobile Internet Devices, PDAs, Mobile Phones Google Chrome OS


Offshore Outsourcing The Internet enables individuals or businesses to

contact freelancers from all over the world to get project done at a lover cost. Product manufacturing/development can be

anywhere cheap. Timezone benefits Nearshore outsourcing – for common timezone

General criteria Wage differences On-line worker The work can be transmitted over the Internet


(cont'd.) Four basic types:

Information Technology Web site management, system monitoring and

administration, ... Business Process

Call centers, insurance claims, taxation, ... Software R&D

Programming, testing, translation, ... Knowledge Process

Those require higher skills e.g., medical, investment research, accounting functions, document translations, design and engineering


Social Social network services enable new forms of

social interaction, activities, and organizing. Tied by types of interdependency such as friendship,

kinship, belief, knowledge, like, dislike, .. Social network sites

Facebook ~ 400M users MySpace Hi5 Twitter ~ #WeLoveKing LinkedIn ~ professional Wakoopa ~ software


Global Digital Divide


(cont'd.)


(cont'd.) “The troubling gap between those who use computers

and the Internet and those who do not” - Bharat Mehra

Without enough ICT infrastructure, some countries fall behind in technology, education, labor, democracy, and tourism. Rural Internet One Laptop per Child


Privacy and Security

“Privacy is dead – get over it”

Steve RambamPrivate Investigator


Internet Privacy The ability to control what information one

reveals about oneself over the Internet, and to control who can access the information.

It is possible to link the Internet activities to personally-identifiable information. e.g., cookies, photographs, logs, keywords searched,

sites visited.. The recent case of MICT – sniffer Anonymizer

I2P – Invisible Internet Project Tor – The Onion Router


Internet Security Security concerns

Confidentiality Integrity Availability

Vulnerabilities Design, Hardware, Software, Human

Threats Malware: viruses, trojans, worms, spyware, bots Theft: information, identity, infrastructure Social engineering: phishing, frauds Natural disasters


Computer-Related Crime Act


The Future Internet Currently, we are using IPv4, and we are running

out of IP addresses. 32-bit address space

Today's Internet is dying, the x-day would be around 2011-2012

19831984

19851986

19871988

19891990

19911992

19931994

19951996

19971998

19992000

20012002

20032004

20052006

20072008

2009

219 217 216 215 214 206195 186

168154

144134 128 124 122 118 116 111 106 102 97 89

7867

5234 26

Num

ber o

f /8

bloc

ks a

vaila

ble


(cont'd.) This year, we will migrate to IPv6.

340 282366 920938 463463 374607 431768 211456 About 7 addresses per atom of every person on

earth. The worst case: ~1,500 addresses for every square

meter of earth's surface. Better packet processing New services.

Multicast Mobility Security ...


(cont'd.) The web may be evolved to the semantic web

Meaning (semantics) of information and services on the web is defined.

Understandable by the machine, so that the processing can be automatic.

Tim Berners-Lee has describe the semantic web as a component of Web 3.0.

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