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The Internet & The World Wide Web

Magister Teknik Elektro

Pertemuan II

September 2010

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• Start from Morse Code, then telegraph, etc.

• The largest network of networks in the world.

• Uses TCP/IP protocols and packet switching .

• Runs on any communications substrate.

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A Brief Summary of the Evolution of the Internet

1945 1995

Memex Conceived

1945

WWWCreated

1989

MosaicCreated

1993

A Mathematical

Theory of Communication

1948

Packet Switching Invented

1964

SiliconChip1958

First Vast ComputerNetwork

Envisioned1962

ARPANET1969

TCP/IPCreated

1972

InternetNamed

and Goes

TCP/IP1984

HypertextInvented

1965

Age ofeCommerce

Begins1995

Copyright 2002, William F. Slater, III, Chicago, IL, USA

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Access Device & Physical Connection

• Bandwidth: volume of data can be sent/received through a communications channel in a given amount of time

• bps• Hertz

• Principal means of connection• Telephone (dial-up modem)• Several high speed phone lines: ISDN, DSL, T1• Cable modem• Wireless: satellite, etc.

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Connection Max Speed (download)

Notes

Telephone 56 kbps Inexpensive, easy to get

ISDN 128 kbps Faster than dial-up, uses conventional phone lines

DSL 1.5 – 8.4 Mbps Fast download, always on, higher security

T1 line 1.5 Mbps Support many users, reliable high speed both ways

Cable modem 10 Mbps Fast, always on, support many users

Satellite 400 kbps Wireless, fast, reliable

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• ISDN• Allows voice, video, data to be communicated over traditional

copper-wire telephone lines• able to send signals over POTS lines

• xDSL (Digital Subscriber Line)• Uses regular phone lines with DSL modem• ADSL, SDSL, HDSL, etc

• T1 line• A traditional trunk line that carries 24 normal telephone

circuits with transmission rate of 1.5 Mbps• T3 line transmits at 44 Mbps• STS-1 runs at 51 Mbps• STS – 48 connection speeds data along at 2.5 Gbps

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• Cable modem• Connects PC to a cable TV system that offers an

Internet connection• Always on• Sharing the system with the neighbors: slower

(peak load times), more vulnerability (from hackers)

• Wireless systems

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ISP

• ISP (Internet Service Provider)• A company that connects you through your

communications line to its servers, which connect you to the Internet via another company’s network access points

• Costs• Access• Support• Reliability

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WWW• Surfing or browsing on the Web and email

are popular use of the Internet

• Multimedia form– What makes the Web graphically inviting

• Use of hypertext – What makes the Web easily navigable– A system in which documents in many

Internet sites are directly link – with hyperlinks – so that a word or phrase in one document becomes a connection to a document in a different place

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– Hyper-Text Markup Language (HTML) : the set of special instructions that are used to specify document structure, formatting, and links to other multimedia documents.

• http://www.unud.ac.id/ind/penerimaan-mahasiswa-baru-program-studi-hubungan-internasional-dan-sosiologi-tahun-2009.html

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• Website – domain in the computer• A computer with a domain name is called a site• www.detik.com & www.kompas.com

• Web pages – the documents on a website• A website is composed of a web page or collection

of related web pages http://nasional.kompas.com/read/xml/2009/09/17/17215334/Akhir.Pelarian.Sang.Buron.9.Tahun

• A document on the www that can include text, pictures, sound, and video

• The first page is like the title page of a book – a homepage : www.kompas.com or www.unud.ac.id

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• Browsers• Software for connecting with websites• Software that enables users to view web pages

and to jump from one page to another• Microsoft Internet Explorer, Netscape Navigator,

etc.

• URLs – addresses for web pages• Uniform Resource Locator • A string of characters that points to a specific piece

of information anywhere on the Web• Website’s unique address

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• URL consists of– The web protocol– The name of the web server– The directory (folder) on that server– The file within that directory (.html or .htm)– http://www.balipost.go.id/keluarga/artikel1.htm

• http:// - protocol: set of communication rules for exchanging information

• www.balipost.go.id - the web server • Keluarga – directory in the server• Artikel1.htm – a file in html

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• Be careful do browsing– Know the source

• www.internic.net use the Registry Whois link to search the database of registered domain names

• InterNIC—Public Information Regarding Internet Domain Name Registration Services

– A tilde (~) • Usually a sign of a personal site – run by an

individual• E.g. http://staff.unud.ac.id/~linawati

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• Web portals– Websites that group together in one

convenient location popular features such as search tools, email, electronic commerce, and discussion groups

• Yahoo, altavista, lycos, etc.• http://www.unescobkk.org/

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• Multimedia on the web– Plug-ins

• External application files had to be loaded into the system

• Or is called a player or a viewer • E.g. Acrobat Reader, Flash Player, Media Player,

Quick Time, etc.

– Developing multimedia – applets, Java, JavaScript, and ActiveX

– Streaming video / audio• The process of transferring data in a continuous

flow so that you can begin viewing / listening a file even before the end of the file is sent.

• Realplayer, RealAudio, etc.

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• Push technology & webcasting– Push technology, software that automatically

downloads information to your computer• E.g. updating software or antivirus application

– Webcasting (one result of push technology)• Customized text, video, and audio are sent to you

automatically on a regular basis• Webcast, webinars, livestreaming, flashstreaming,

webconference, etc. • A webcast is a way of broadcasting over the

Internet — analogous to a broadcast television program.

• The primary purpose of a webcast is to transmit a message to a large number of people

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• Web conferences– used to conduct live meetings or presentations where

you can sit at your own computer and can connect to other participants via the Internet.

• A webinar– a specific type of web conference — a web-based

seminar. – It is typically one-way, from the speaker to the

audience. – can be very collaborative and include polling and

question and answer sessions. – In some cases, the presenter may speak over a

standard telephone line, pointing out information being presented on-screen and the audience can respond over their own telephones

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• The Internet Telephone & Videophone• Audio conferencing• Video conferencing

• Other Internet applications• FTP (file transfer protocol)

– A method whereby a computer can connect to a remote computer and transfer files

– E.g. smartFTP, cuteFTP, etc.

• Telnet– A program that enables user to communicate with other

computers and is typically used for remote access to host computers on which user has an account

• Newsgroups• RTC (real-time chat)

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Software Services• Archie

• A collection of resource discovery tools, developed and maintained by McGill Univ, for locating files at hundreds of anonymous FTP sites by using a file name search

• Gopher• combines features of electronic bulletin board services and

databases with parts of FTP, Archie, WAIS, and Telnet into one easy-to-use navigation tool.

• It simplifies locating and retrieving ASCII text documents from various sources of information

• Veronica (Very easy rodent-oriented net-wise index to computerized archives)

• Service that locates and indexes titles of Gopher items by keyword search. A veronica search typically searches the menus of hundreds of Gopher services, perhaps all the Gopher servers that are attached to the Internet

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• WhoIs• Provides information on registered users and network

names, including their postal addresses. The main WhoIs database runs at the Network Information Centre (NIC) with administrative and technical contacts for domains automatically registered when the applications are processed.

• WAIS• Wide Area Information Server • a client – server system developed to help users search

multiple Internet sites at one time and retrieve resources by searching indexes of databases.

• WWW• World Wide Web retrieves resources as a powerful

hypertext and hypermedia browser of databases. Hypertext is text with pointers to other text. Hypermedia might also involve images, sound, or animation, in addition to text.

• This public domain software goes beyond Gopher and WAIS as a global information system with an easy-to-use interface that provides access to almost all existing Internet-based information. The information appears on homepage.

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• HTML• HyperText Markup Language is one of the capabilities that

is used like a word processor to create a WWW homepage. • Is a language, a standard for creating multimedia, hypertext

files, and a standard for serving these standardized files when they are requested.

• HTTP• HyperText Transfer Protocol is the standard used by the

server and its clients, which will send HTML files over the Internet from the server to clients requesting them.

• http:// on the WWW to access a homepage, that is, a site with HTML documents

• Mosaic• A hyperlink – based Internet information browser and world

wide web client that provides transparent access to a number of resources, including anonymous FTP, WAIS, and WWW.

• Netscape• A premier graphics and hyper-based Internet information

presenter and browser, similar to Mosaic. One feature is the access to search engines.

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• Explorer• Microsoft cooperation’s competitor to Netscape

• Java• A simple, object-oriented, distributed, interpreted,

robust, secure, architecture neutral, portable, high-performance, multithreaded, and dynamic language.

• Etc

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Jargons on Internet

• Browser• Software that opens the door of the web, allowing

the display of text and graphics

• FAQ• Frequently asked questions: a grab bag of

questions that new users of a web site often ask – with answers, of course

• Hit• A rough measure of a site’s popularity; each hit

represents one time that a file in the site is accessed

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• Homepage• The opening screen of a web-site

• Hypermedia• Video and sound files transmitted by way of the Web

• Hypertext• Highlighted text linked to related pages in the same or other sites

• Search engine• An electronic directory on the web that search for documents,

pages, or sites based on a keyword

• Website• A collection of pages and files on the Web built around a common

theme or subject

• Webmaster• The authority figure responsible for maintaining and updating the

information of a site

• URL• Universal Resource Locater is the technical name of a web address

– http://www.apple.com is an example

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E-mail• Email software

• Eudora, Outlook Express, Lotus Notes

• Email address• A domain: a simple a location on the Internet• E.g. linawati@unud.ac.id • Unud.ac.id domain name• Unud domain (location), ac domain type, id

country• Check on whether the address is available, as

well, and register it by going to www.register.com or www.internic.net/regist/html

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• Instant messaging• Any user on a given email system can send a

message and have it pop up instantly on the screen of anyone else logged onto that system

• Typed conversations in real time• Yahoo Messenger, MSN Messenger, etc.

• Mailing list • Email based on discussion groups• To be a member – subscribing & unsubscribing • A directory of mailing lists is available at Publicly

Accessible Mailing Lists (http://paml.net) or Yahoo!’s OneList (www.onelist.com)

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Netiquette: appropriate online behavior

• Consult FAQs• Avoid flaming

• Flaming is a form of public humiliation inflicted on people who have failed to read FAQs or otherwise not observed netiquette.

• Don’t shout• Avoid use of all-capital letters. It is considered the equivalent of

SHOUTING

• Avoid sloppiness, but avoid criticizing other’s sloppiness• Such as avoid spelling and grammatical errors

• Don’t send huge file attachments, unless requested• Different bandwidth, capacity, and storage

• When replying, quote only the relevant portion

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• Some emoticons– Happy face :-)– Sorrow or frown :-(– Shock :-o– Sarcasm :-/– Wink ;-)– Grin <g>– By the way BTW– In my humble opinion IMHO– For your information FYI

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• Spam : unwanted junk email– Delete without opening the message : virus– Never reply to a spam message– Enlist the help of your ISP or use spam filters

• E.g. Earthlink’s Spaminator• ImagiNet (www.imagin.net) , www.brigthmail.com,

www.spamkiller.com, www.hms.com

– Fight back• Report to (www.abuse.net) , www.rahul.net/falk • These will tell you where to report spammers, the

appropriate people to complain to, and other spam-fighting tips