Transcript Internet

Technology Guide 5
The Internet & the Web
1
What is the ‘Internet’?
 The Internet (“the Net”) is a network that connects hundreds of
thousands of internal organizational computer networks
worldwide.
 Participating computer systems, called nodes, include PCs, local
area networks, database(s), and mainframes.
 A node may include several networks of an organization,
possibly connected by a wide area network.
 The Internet connects to hundreds of thousands of computer
networks in more than 200 countries.
2
The History of the Internet
 The Internet grew out of an experimental project of the Advanced
Research Project Agency (ARPA) of the U.S. Department of Defense.
 The project was initiated in 1969 to test the feasibility of a wide area
computer network.
 The main network that links the nodes is referred to as the backbone, a
fiber-optic network currently operated mainly by telecommunication
companies such as MCI.
 No central agency manages the Internet. The cost of its operation is
shared among hundreds of thousands of nodes.
3
Next Generation Internet Services
 Very High-Speed Backbone Network Service (vBNS) is a
high-speed network designed to support the academic Internet2
and the government-sponsored Next-Generation Internet (NGI)
initiative
 Internet2 is a collaborative effort by large U.S. research
universities, working with industry and government, to develop
advanced Internet technologies.
 The Next-Generation Internet (NGI) initiative is a multiagency,
U.S. federal government research and development program that is
developing advanced networking technologies and revolutionary
applications.
4
Accessing the Internet
 PC and modem
 From home
 From work or school, via
the organization’s LAN
 Television set, a special
connection device, and a
telephone connection.
 Combined PC and TV
 Internet kiosks are
terminals placed in public
places like libraries and
coffee houses.
 Cell phones and pagers are
becoming another popular
way of accessing the
Internet.
5
The TCP/IP Protocol
 Procedures and rules for transferring data across the Internet are
called telecommunication protocols.
 The information that passes through the Internet is divided into
small portions, called packets.
 One member of the TCP/IP family of protocols is Telnet, a
service that allows users to connect to computers other than their
own.
6
Internet Resources
 An online service sells access to large (usually nationwide)
databases.
 Several magazines deal exclusively or mainly with the Internet.
 Internet Business Advantage, Internet World , NetGuide, Wired
 There are also many organizations involved in Internet activities.
 Internet Society (isoc.org), Electronic Frontier Foundation (eff.org)
 Wide area information servers (WAIS) is an Internet directory
designed to help end-users find and retrieve information over the
networks by providing efficient search methods.
7
The World Wide Web
 The World Wide Web (or “the Web”) is a vast collection of
interconnected pages of information that are stored on computers
around the world that are connected to the Internet.
 A Web site is a computer network, such as the one in your university,
that has a connection to the Internet.
 The Web is based upon a set of standards for storing, retrieving, and
manipulating information, using a special tool called a Web browser.
 Documents accessible on the Web contain hyperlinks to other
documents.
 The home page is the starting point for your search.
8
Web Programming Languages
 The most common web programming language is HyperText
Markup Language (HTML).
 Another programming language, Java, makes it is easy to
develop special applications in finance, manufacturing,
marketing, and education.
 A technology that has evolved from Java is called Jini, a network
protocol that sends messages to other parts of the network.
 e.g, If a new printer is added to a network, it can tell the PCs on the
network that it is there via the Jini protocol.
9
Search Engines
 A search engine is a tool that enables you to locate information
by using key words in the same way that you would search
online library resources.
 Google, Yahoo, Lycos, HotBot, WebCrawler, Alta Vista, and Excite.
 To get better even results, metasearch engines integrate the
findings of the various search engines to answer queries posted
by the users.
 Spider, Savvy Search, Metacrawler, All-in-One, and Web Compass
10
Using the Internet
 A uniform resource locator (URL) indicates the location (or address)
of a Web site you want to visit.
 A predecessor to the Web, Gopher, is a “burrowing tool” that provides
access to a wide range of textual information available on the Internet.
 Many software packages can be downloaded on the WWW.
 Some are free as public domain (cheapware).
 Others are called shareware, meaning you can use them on a trial basis.
 Many of the documents are transferable from the Internet using a
member of the TCP/IP family called file transfer protocol (FTP).
11
Electronic mail
 Electronic mail (e-mail) allows multiple-access communication
delivered exclusively on a computer network.
 Several vendors produce e-mail software.
 e.g., Microsoft Outlook, LotusNotes, QuickMail
 E-mail is also becoming connected to voice mail, and sometimes
the two are integrated.
 Many Web-based e-mail providers offer e-mail accounts for free.
 e.g., Hotmail, Coolmail, and Yahoo! Mail
12
Chat Rooms & Newsgroups
 Chat programs allow you to send messages to people who are
connected to the same channel of communication at the same
time. There are two main types;
 Webchat allows you to send messages to Net users using a Web
browser and visiting a Webchat site.
 Internet Relay Chat (IRC) is an e-mail-based (text only) program
often used in business.
 Newsgroups communicate via messages posted in a different
time/different place mode. The groups are organized in a
directory according to categories and subcategories.
13
Mailing Lists & Electronic Bulletin Boards
 Mailing Lists are a useful way of communicating to large groups.
 To add your e-mail name and address to a mailing list, you
subscribe; to remove your name, you unsubscribe from the
mailing list.
 Electronic bulletin boards (EBBs) are mailing lists on which
users can leave messages for other people and receive massive
amounts of information.
 A portal is a Web site designed to offer a variety of Internet
services from a single convenient location.
 e.g., Altavista, Excite, Lycos, Yahoo!
14
Wireless Application Protocol (WAP)
 Wireless Application Protocol (WAP) provides a universal
open standard that enables users to access Web-based
interactive information services and applications from the
screens of mobile phones.
 The communication language being used between the Internet
and the mobile phone is Wireless Markup Language (WML).
 It is expected that in 2002, more than half of the e-commerce
transactions will be conducted with mobile phones.
15