Web Application Technologies - FTMS · 2019. 2. 19. · Internet Applications - E-mail • Short...
Transcript of Web Application Technologies - FTMS · 2019. 2. 19. · Internet Applications - E-mail • Short...
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Web Application Technologies
Chapter 1
Introduction to Internet
Chapter 1 – Introduction to Internet
What is The Internet?
• The Internet is a global
connection of computers.
• These computers are
connected through Wide
Area Network (WAN).
Chapter 1 – Introduction to Internet
The Internet Usages
• Exchange of data, news and opinion.
• Upload and download files.
• Electronic Mail (E-Mail)
• Communicate and socialize
• Marketing
• Online banking
• Online shopping
• Entertainment
Chapter 1 – Introduction to Internet
History of The Internet
• The Internet originated in the late 1960s when the United States Defense Department developed ARPAnet (Advanced Research Projects Agency network), an experimental network of computers designed to withstand partial outages such as a bomb attack.
• The agency sought to create a web of computers that could continue to communicate with each other, even if some of the computers were disabled.
Chapter 1 – Introduction to Internet
History of The Internet
• In the mid-1980s, when desktop computer workstations became increasingly popular, organizations wanted to connect their local area networks (LANs) to ARPAnet. If computers could link together and share resources, everyone would benefit.
Chapter 1 – Introduction to Internet
History of The Internet
• 1991 was a big year for the Internet: The National Research and Education Network (NREN) was founded and the World Wide Web was released.
• The Internet is still dominated by scientists and other academics, but begins to attract public interest.
Chapter 1 – Introduction to Internet
History of The Internet
• With the release of the Mosaic Web browser in 1993 and Netscape in 1994, interest in and use of the World Wide Web exploded.
• More and more communities become wired, enabling direct connections to the Internet.
Chapter 1 – Introduction to Internet
How Does the Internet Works?
• The unique thing about the Internet is that it allows
many different computers to connect and talk to each
other.
• This is possible because of a set of standards, known
as protocols, that govern the transmission of data
over the network: TCP/IP (Transmission Control
Protocol/Internet Protocol).
• All computers must use same protocol.
• To gain access to the Internet, the user need to
register to any Internet Service Provider (ISP).
Chapter 1 – Introduction to Internet
How Does the Internet Works?
• Each computer on the Internet is called the host
computer.
• Many of the host computer on the internet offer
services to other computers on the Internet.
• Computer which provides services for other
computers is called server.
• A host computer may run mail servers, web server,
FTP server, IRC server, etc.
Chapter 1 – Introduction to Internet
The Internet Requirements
• Computer with modem / network card
• Internet connection
• Account with Internet Service Provider (ISP)
• Web browser
– Example: Internet Explorer, Firefox, Opera
• 3rd-party software
– Example: Flash player, QuickTime Player, Adobe
Reader
Chapter 1 – Introduction to Internet
Internet Connections
• Dialup is naturally the slowest type of connection to
the Internet. It runs over analog telephone lines, and
its speed is limited by the quality of these lines, which
were designed for low-quality voice calls, not data
transmissions. Dialup relies on modems (modulator-
demodulators), which max out at 57600 bps (in
practice, 53000 bps).
Chapter 1 – Introduction to Internet
Internet Connections
• ISDN (Integrated Services Digital Network) is a digital
connection over a conventional telephone line.
• It is not in common use, because it has been
supplanted by DSL.
• ISDN offers speeds up to twice as fast as dialup.
Chapter 1 – Introduction to Internet
Internet Connections
• DSL (digital subscriber line) sends signals on a higher
frequency than voice signals over telephone lines. It offers high
speeds, but bandwidth degrades as the length of the telephone
line increases from the modem to the telephone company's
central office
• DSL comes in two flavours:
– ADSL - Asynchronous DSL means that uploading is much
slower than downloading. Internet service providers (ISPs)
adopt this technology so that they can spend less on
bandwidth and so that they discourage users from running
bandwidth-intensive servers.
– SDSL - Synchronous DSL provides equally fast
upstream/downstream bandwidth. SDSL is expensive and
generally used by businesses hosting web servers.
Chapter 1 – Introduction to Internet
Internet Connections
• Cable uses television coaxial cable to connect to the
Internet.
• Cable has the potential to offer very high speeds, but
is limited because cable is shared in a
neighbourhood.
• If the aggregate bandwidth being used by customers
exceeds the bandwidth of the physical cable
connection in a neighbourhood, then slowdowns are
observed.
Chapter 1 – Introduction to Internet
Internet Connections
• Satellite also comes in two types:
– Modem-Satellite - A modem is used to send
upstream data requests, while a dish receives
data from a satellite. This method is plagued by
latency, as it takes a long time for a request to
travel via dial-up to the web server in question,
and for the response to arrive through the satellite
system.
– Satellite two-way - The satellite dish sends and
receives data. This technology is more recent, but
still suffers from latency problems, simply because
satellites are far away.
Chapter 1 – Introduction to Internet
Internet Connections
• Corporations may use T1, T3, and above for hosting
web servers, serving office users, and so forth.
• These lines are dedicated digital trunks, reliable, and
fast, but prohibitively expensive for home users.
Chapter 1 – Introduction to Internet
Internet Connections
Chapter 1 – Introduction to Internet
Internet Applications
• An Internet application is an interactive, compiled application that can be accessed through a corporate or through the .
• Internet applications can perform complex business processes on either the client or the server.
• In a server-based Internet application, the application uses the Internet protocol to receive requests from a client, typically a Web browser, process associated code, and return data to the browser.
Chapter 1 – Introduction to Internet
Internet Applications
1. World Wide Web
2. Search Engine
3. E-mail
4. FTP
5. WHOIS
6. Telnet
7. WAIS
8. Gopher
9. Ping
10. Traceroute
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - World Wide Web
• The World Wide Web, or simply Web, is a way of accessing information over the medium of the Internet.
• It is an information-sharing model that is built on top of the Internet.
• The Web uses the HTTP (HyperText
Transfer Protocol), only one of the
languages spoken over the Internet,
to transmit data.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - World Wide Web
• The Web also utilizes browsers, such as Internet Explorer or Firefox, to access Web documents called Web pages that are linked to each other via hyperlinks.
• The web documents are formatted in a markup language called HTML (HyperText Markup Language) that supports links to other documents, as well as graphics, audio, and video files.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - World Wide Web
Advantages of World Wide Web
• Easy linking of documents to other documents.
• Content is simple to create and make available for
use.
• Support for mixed multimedia elements.
• Open standards.
• Accessible for everyone.
• Facilities the publication, dissemination and sharing
of information on a global basis.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - World Wide Web
Website vs. Web page
• A website is a collection of one or more web pages
designed to convey information on a particular
subject or theme to a web user.
• A web page is one screen full of information (from a
web site) that may contain links to other pages in the
web site or links to external information. The web
page will normally be written as (or rendered as) an
HTML document.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - World Wide Web
Uniform Resource Locator (URL)
• The global address of documents and other resources on the World Wide Web.
• A URL can be typed into the address bar.
• It consists of three parts:
– A protocol name
– A host part
– A document name
• Example:
– http://www.yahoo.com
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Search Engine
• Search engines are programs that search documents
for specified keywords and returns a list of the
documents where the keywords were found.
• Examples: Yahoo!, Google, Altavista, Lycos,
Metacrawler, and Hotbot.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Search Engine
• Search engines work by sending out a spider to
fetch as many documents as possible.
• Another program, called an indexer, then reads
these documents and creates an index based on the
words contained in each document.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Gopher
• A system that pre-dates the World Wide Web for
organizing and displaying files on Internet
servers.
• A Gopher server presents its contents as a
hierarchically structured list of files.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - File Transfer Protocol (FTP)
• The protocol for exchanging files over the Internet.
• FTP is most commonly used to download a file from
a server using the Internet or to upload a file to a
server.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Telnet
• Telnet is an application used on the internet to
connect to a remote computer, enabling access to
the computer and its resources.
• A protocol that enables a user on one machine to log
onto another networked machine.
• This enables you to control the server and
communicate with other servers on the network.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - E-mail
• Short for Electronic Mail.
• The transmission of messages over communications networks.
• Email allows you to:
– Sent and Receive message
– Forward message
– Send attachment
• Used two different protocols:
– Simple Mail Transfer Protocol (SMTP)
– Post Office Protocol (POP) / Internet Message Access Protocol (IMAP)
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Email
• Email address consist of three parts:
– User name
– @ sign
– Server name
• Example:
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Email
Email Client
• An application that runs on a personal computer or workstation and enables you to send, receive and organize e-mail.
• The advantage of using an email client is that the emails are stored on your computer and are accessible faster than using a web based email interface.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Email
Email Client
Examples:
• Outlook
• Outlook Express
• Thunderbird
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Email
Webmail
• Webmail (or Web-based e-mail) is an e-mail service
intended to be primarily accessed via a web browser.
• They allow you to check your email from any
computer that has an Internet connection.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Email
Webmail
• Example:
– Gmail
– Yahoo! Mail
– Hotmail.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - WHOIS
• An Internet utility that returns information about a
domain name or IP address.
• NSLOOKUP is another application that has similar
function as WHOIS.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Finger
• A program that takes an e-mail address as input and
returns information about the user who owns that e-
mail address.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Wide Area Information Server
(WAIS)
• Wide Area Information Server (pronounced ways),
is a program for finding documents on the Internet.
• WAIS is rather primitive in its search capabilities.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Usenet/Newsgroup
• A worldwide bulletin board system that can be
accessed through the Internet or through many
online services.
• It consists of a set of "newsgroups" with names that
are classified hierarchically by subject.
• "Articles" or "messages" are "posted" to these
newsgroups by people on computers with the
appropriate software.
• It uses a protocol called Network News Transfer
Protocol (NNTP).
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Usenet/Newsgroup
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Ping
• Ping is a computer network administration utility used
to test the reachability of a host on an Internet
Protocol (IP) network and to measure the round-trip
time for messages sent from the originating host to a
destination computer.
• A utility to determine whether a specific IP address is
accessible.
• It works by sending a packet to the specified address
and waiting for a reply.
• PING is used primarily to troubleshoot Internet
connections.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Ping
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Traceroute
• A utility that traces a packet from your computer to an
Internet host, showing how many hops the packet
requires to reach the host and how long each hop
takes.
• If you're visiting a Web site and pages are appearing
slowly, you can use traceroute to figure out where the
longest delays are occurring.
Chapter 1 – Introduction to Internet and World Wide
Web
Internet Applications - Traceroute