1 Internet Applications. 2 Objectives Become familiar with… u the Internet, u FTP and Telnet, u...
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Transcript of 1 Internet Applications. 2 Objectives Become familiar with… u the Internet, u FTP and Telnet, u...
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Internet Applications
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Objectives
Become familiar with… the Internet, FTP and Telnet, several different types of groupware, electronic commerce,
Understand how the Web and e-mail operate.
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Internet Application Software
There are four important Internet application software tools• the Web• electronic mail (e-mail)• FTP• Telnet
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Internet Application Software
Electronic mail, Telnet, and FTP have been around as long as the Internet itself. The Web, however, was developed in the early 1990s.
These applications were originally developed for the Internet, but many organizations are using them on their LANs or for private use on the Internet.
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World Wide Web
One of the fastest growing Internet software applications is the World Wide Web.
The Web was first conceived in 1989 by Tim Berners-Lee at the European Laboratory for Particle Physical (CERN) in Geneva.
CERN’s first Web browser was written in 1990, but it was 1991 before it was available on the Internet for other organizations to use.
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How the Web Works
Each client computer needs an applications layer software package called a Web browser.
Each server on the network needs an application layer software package called a Web Server.
In order to get a page from the Web, the user must first type the Internet Uniform Resource Locator (URL) for the page, or click on a link that provides the URL.
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How the Web Works
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How the Web Works
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How the Web Works
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Generic Client/Server Environment
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How the Web Works
In order for the request from the Web browser to be understood by the Web server, they
must use the same standard protocol.
The standard protocol for communication between a Web browser and a Web server is
Hypertext Transfer Protocol (HTTP).
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How the Web Works
An HTTP request from a Web browser to a Web server has three parts. Only the first part is required, the other two are optional.• the request line• the request header• the request body
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How the Web Works
GET http://apollo.saultc.on.ca/~brasheed/ test.html HTTP/1.1Date: Thurs 18 Jan 2001 17:35:46 GMTUser-Agent: Mozilla/3.0From: [email protected]: http://apollo.saultc.on.ca/~brasheed/index.html
Request Header
]- Request Line]- Date
]- Web browser (this is Netscape)
]- User’s e-mail address
Command URL HTTP version
URL that contained the link to the requested URL
A Request from a Web browser to a Web server using the HTTP standard
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How the Web Works
Many people believe that the Web is anonymous. However, every Web access must provide the Internet address of the requester’s computer; otherwise the server would not know where to send the requested page.
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How the Web Works
The format of an HTTP response from the server to the browser is very similar to the browser request.
Only the last part is required, the other two are optional.• the response status• the response header• the response body
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A response from a Web server to a Web browser using the HTTP standard
HTTP version Status code Reason phrase
Response Header
HTTP/1.1 200 OKDate: Mon 03 Aug 1998 17:35:46 GMTServer: apache1.3Location: http://apollo.saultc.on.ca/~brasheed/ test.html Content-type: text/html
<html><head><title>Test Page </title></head><body><H2> Test Web Page: </H2><P>If you can see this page from your browser that means your server is working fine. </P><P ALIGN="CENTER"> <A HREF="http://apollo.saultc.on.ca/">Computer Studies Home Page</A> </P></body></html>
ResponseBody
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How the Web Works
Hypertext Markup Language (HTML), the most commonly used Web format, was developed by CERN at the same time as the first web browser.
HTML is fairly easy to learn, so you can develop your own Web pages.
The only certainty about the Web is that it will change.
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Finding Information
The key problem with the Web is finding the information you need. There is no formal directory of all Web pages because almost anyone can develop and post a page on a Web server.
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Finding Information
There are three ways to discover interesting and useful Web pages:
1. Someone could tell you about a page, or you could read an advertisement listing the Web address.
2. You could find a link from one page to another.
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Finding Information
3. You could use a search engine.Search engines are Web sites that routinely use
software spiders to explore the Web. There are literally dozens of search engines and directories on the Web. Three of the best are:
Yahoo Altavista Excite
A metasearch engine (like MetaCrawler) simultaneously sends requests to many search engines and then integrates the responses.
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Webcasting
Webcasting is a special application of the web in which the user signs up for a type of information on a set of channels.
Webcasting changes the nature of the Web from the user searching for information (“pull”) to accepting information from the Webcast server (“push”).
Webcasting can be used for news or financial reports, corporate announcements, and as a replacement for broadcast e-mail.
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Electronic Mail
Electronic mail (e-mail) was one of the earliest applications on the Internet and is still among the most heavily used today.
Most e-mail packages allow you to do the same things you do with regular paper mail.
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Electronic Mail
E-mail has several advantages over regular mail:1. It is fast (arrives in seconds or minutes).
2. It is cheaper (costs virtually nothing)
E-mail can substitute for the telephone, allowing you to avoid telephone tag.
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E-mail Standards
Several standards have been developed to ensure compatibility between different e-mail software packages.
Three most commonly used standards are:• SMTP• X.400• CMC
All three e-mail standards work in the same basic fashion.
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E-mail Clients & Servers
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Single System
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Network of Mail Systems
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E-mail Standards
Each client computer in the LAN runs an application layer software package called a user agent, which formats the message into two parts:• The header (source & destination address)• The body (message)
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E-mail Standards
The user sends the message to a mail server that runs a special application layer software package called a message transfer agent, which reads the header and sends the message through the network to the receiver’s mail server, where it is stored in the receiver’s mailbox.
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E-mail Standards
When the receiver next accesses his or her e-mail, the user agent on his or her computer contacts the mail transfer agent on the mail server and requests the contents of the mailbox, which the user reads with the user agent.
The Simple Mail Transfer Protocol (SMTP) is one of the most commonly used e-mail standards simply because it is the e-mail standard used on the Internet.
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E-mail Standards
TO: “Pat Someone” <[email protected]>From: “Bazlur Rasheed;”<[email protected]>Date: Thurs 18 Jan 2001 17:35:46 GMTSubject: Sample NoteDATA: This is an example of an e-mail message
Message Header
]- Message Body
An example of an e-mail message using the SMTP standard
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E-mail Standards
The SMTP standards covers message transmission between message transfer agents.
A different standard called Post Office Protocol (POP) defines how user agents operate and how messages to and from mail transfer agents are formatted.
POP is gradually being replaced by a newer standard called Internet Mail Access Protocol (IMAP).
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E-mail Standards
Two other commonly used e-mail standards are X.400 and CMC, which are different from SMTP, POP and IMAP, so that they cannot be used interchangeably.
The X.400 e-mail standards was developed by CCITT in 1984.
The Common Messaging Calls (CMC) standard is a simpler version of the X.400 standard, developed by CCITT with IBM, Lotus and Microsoft in 1994.
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E-mail Directories
Before you can send an e-mail message, you must know the receiver’s e-mail address. Currently there are no universal e-mail directories.
Several computing standards have been developed in an attempt to provide this universal directory, but as yet little progress has been made to actually implement a worldwide system based on the standards.
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E-mail Directories
X.500 is the directory service for X.400 mail users, but at present there are few standard application software packages that conform to X.500.
Lightweight Directory Access Protocol (LDAP) is a subset of X.500.
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File Transfer Protocol (FTP)
File Transfer Protocol (FTP) enables you to send and receive files over the Internet.
There are two types of FTP sites: • Closed (requires users to have permission before they
can connect and gain access to files)• Anonymous (permits any Internet user to login using
the account name of Anonymous)
Many files and documents available via FTP have been compressed to reduce the amount of disk space they require.
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Telnet
Telnet enables users on one computer to login into other computers on the Internet.
Telnet can be useful because it enables you to access your server or host computer without sitting at its keyboard.
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GROUPWARE
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Groupware
Software that helps groups of people to work together more productively.
Group support system
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Groupware
Groupware allows people to exchange ideas, debate issues, make decisions, and write reports without actually having to meet face-to-face.
There are four popular types of groupware:• Discussion groups• Document-based groupware• Group support systems• Videoconferencing
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Discussion Groups
Discussion groups are Internet users who have joined together to discuss some topic.
Two discussion groups commonly used for business:• Usenet Newsgroups• Listservs
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Usenet Newsgroups
Usenet Newsgroups are the most formally organized of the discussion groups.
The newsgroups are just a series of discussions about each topic.
The exact commands to gain access to these newsgroups varies from computer to computer.
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Listservs
Listserver (Listserv) group is similar in concept to the usenet newsgroups but is generally less formal.
One part, the listserv processor, processes commands such as requests to subscribe, unsubscribe, or to provide more information about the listserv.
The second part is the listserv mailer. Any message sent to the listserv mailer is re-sent to everyone on the mailing list.
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Document-based Groupware
E-mail lacks a structured way to support an ongoing discussion.
A document database (like Lotus Notes) designed to store and manage large collections of text and graphics was the first solution.
Lotus domino
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Document-based Groupware
Lotus Notes can also be used to organize a discussion among certain people (a project team working to improve manufacturing quality).
Lotus Notes can also automate certain document-based processes (called work-flow automation).
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Document-based Groupware
One of Notes’ greatest strengths is its replication ability (the automatic sharing of information among servers when information changes).
More than 2 million people world-wide now use Lotus Notes.
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Group Support Systems
Both e-mail and document-based groupware are designed to support individuals and groups working in different places and different times.
Group Support Systems (GSS) are software tools designed to improve group decision making.
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Group Support Systems
In a GSS meeting, group members can discuss idea verbally as they could in any meeting room; however, they can also use the computer to type ideas and information, which are then shared with all other group members via the network.
With large groups, however, typing ideas is faster than talking because only one person can speak at a time.
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Group Support Systems
GSS enables users to make comments anonymously.
These systems also provide tools to support voting and ranking of alternatives, so that more structured decision-making processes can be used.
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Videoconferencing
Discussion groups, document-based groupware, and GSS all focus on the transmission of text and graphical images.
Videoconferencing provides real-time transmission of video and audio signals to enable people in two or more locations to have a meeting.
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Desktop Videoconferencing
The fastest growing form of videoconferencing is desktop videoconferencing.
Small cameras installed on top of each computer permit meetings to take place from individual offices.
The key benefits of videoconferencing area the time and cost savings that can result.
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Desktop Videoconferencing
The transmission of video requires a lot of network capacity.
Like e-mail, most videoconferencing systems were originally developed by vendors using different formats so that many products were incompatible.
Three commonly used standards for videoconferencing have the promise to reduce many incompatibilities once adopted: H.320, H.323, and MPEG-1 & -2.
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Managing in a Groupware World
Groupware dramatically changes the way people interact. Communication is simpler and faster.
Nonetheless, groupware’s ability to greatly improve communications can also create problems (e-mail overload).
Social norms are one of the greatest limiting factors in the widespread use of groupware technologies, because technology changes faster than the people who use it.
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ELECTRONIC COMMERCE
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Electronic Commerce
Almost all large and medium-sized companies use the Internet. Many are using it for electronic commerce - doing business on the Internet.
Making money on the Internet is a risky proposition.
Most people automatically focus on the retail aspects of electronic commerce; that is selling products to individuals.
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Electronic Commerce
There are four major ways in which the Web can be used to support electronic commerce:• Electronic store• Electronic marketing• Information/entertainment provider• Customer service
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Electronic store
The most obvious approach to electronic commerce is an electronic store, where a company develops the Internet equivalent of a local store or mail order catalog.
There are many examples of electronic stores.
One of the more interesting electronic stores is that run by Boeing.
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Electronic Store
Since there are few additional costs to providing more information on the Web (unlike a print catalog), electronic stores can provide much information
One problem is verifying the transaction is accurate and is from whom it claims to be from.
A variation on the electronic store is the electronic mall: a collection of electronic stores.
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Electronic Marketing Site
A second common approach is the electronic marketing site which supports the sales process, but does not make the actual sales. The goal is to attract and keep customers.
Many companies use electronic marketing sites to provide newsletters with information on latest products and tips on how to use them. Electronic marketing is cheaper in may ways to traditional marketing.
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Information/Entertainment Provider
An Information/entertainment provider supplies information and/or entertainment.
Information/entertainment providers can be very broad or very focused in topic coverage and can present information in a variety of media.
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Information/Entertainment Provider
Most Web users expect information to be free so most Information/Entertainment Providers doe not charge, although a few require subscriptions before they will allow access.
Like their print counterparts, Information/entertainment providers generate revenue by selling advertising.
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Customer Service
A customer service site provides a variety of information for customers after they have purchased a product or service.
Federal Express has been one of the leading innovators in the use of the Web for customer service.
Customer service sites benefit both the company and its customers.
