Fundamentals of Information Systems Fourth Edition Chapter 4 Telecommunications, the Internet, Intranets, and Extranets

Fundamentals of Information Systems

Fourth Edition

Chapter 4

Telecommunications, the Internet, Intranets, and Extranets

Fundamentals of Information Systems, Fourth Edition 2

Why Learn About Telecommunications and Networks?

• Need to access data wherever it resides

• Fast, reliable communications– Exchange messages– Upload/download data and software– Route business transactions– Connect to remote databases– Send output to printers


An Overview of Telecommunications

• Telecommunications: the electronic transmission of signals for communications

• Telecommunications medium: anything that carries an electronic signal and interfaces between a sending device and a receiving device


An Overview of Telecommunications (continued)

Figure 4.1: Elements of a Telecommunications System


Channel Bandwidth

• Telecommunications professionals consider the capacity of the communications path or channel when they recommend transmission media for a business

• Channel bandwidth: the rate at which data is exchanged over a communication channel– Usually measured in bits per second (bps)– Broadband vs Narrowband


Services

• Digital subscriber line (DSL): telecommunications service that delivers high-speed Internet access to homes and small businesses over the existing phone lines of the local telephone network

• Wireless telecommunications:

All major long distance carriers offer wireless telecommunications services that enable you to place phone calls or access the Internet


Networks and Distributed Processing

• Computer network: the communications media, devices, and software needed to connect two or more computer systems and/or devices

• Network nodes: the computers and devices on the networks


Network Types

• Personal area network (PAN)• Bluetooth refers to the Danish king Harald Bluetooth

Blaatand who unified Denmark and Norway. In the beginning of the Bluetooth wireless technology era, Bluetooth was aimed at unifying the telecom and computing industries.

• Local area network (LAN)


Network Types (continued)

Figure 4.4: A Typical LAN


• Metropolitan area network (MAN)

• Wide area network (WAN)• long distance phone calls; internet access

• International networks• laws regulating transborder data flow

• VoIP systems

• Mesh networking• way to route communications among network nodes

for continuous connections9




Figure 4.5: A Wide Area Network


Distributed Processing

• Centralized processing: all processing occurs in a single location or facility– reduced cost– improve security– simplify backup and recovery

• Decentralized processing: processing devices are placed at various remote locations– suitable for companies with independent operating

divisions

Distributed Processing (continued)

• Distributed processing: computers are placed at remote locations but connected to each other via a network– data can be allocated to locations that can process it

most efficiently– minimizes consequences of a catastropic event (e.g.

9/11 or Katrina)



Client/Server Systems

• Servers: multiple computer platforms are dedicated to special functions, such as database management, printing, communications, and program execution.

• Clients: Access the programs and data available from the servers.


Client/Server Systems (continued)

Figure 4.8: Client/Server Connection


Communications Software and Protocols

• Communications protocol: a set of rules that govern the exchange of information over a communications channel.

• The channels are imperfect, but protocols insure communications are– fast– efficient– error-free


Communications Software

• Network operating system (NOS): systems software that controls the computer systems and devices on a network and allows them to communicate with each other

• Network-management software: software that a manager uses on a networked desktop– Monitors the use of individual computers and shared

hardware (such as printers)– Scans for viruses – Update software and files– Ensures compliance with software licenses


Use and Functioning of the Internet

• Internet: a collection of interconnected networks, all freely exchanging information with no single registration site

Use and Functioningof the Internet (continued)

• Internet Protocol (IP): communication standard that enables traffic to be routed from one network to another as needed



How the Internet Works

• The Internet transmits data from one computer (called a host) to another

• If the receiving computer is on a network to which the first computer is directly connected, it can send the message directly

• If the receiving computer is not on a network to which the sending computer is connected, the sending computer relays the message to another computer that can forward it


How the Internet Works (continued)

Figure 4.11: Routing Messages over the Internet



Data is passed in chunks called packets

Transmission Control Protocol (TCP): widely used transport-layer protocol that is used in combination with IP by most Internet applications

Uniform Resource Locator (URL): an assigned address on the Internet for each computer

• Hypertext Transport Protocol (http): As the default protocol, it can often be omitted


Domain name includes an affiliation code

An internationalized domain name (IDN) is an internet domain name that (potentially) contains non-ASCII characters.


• Country (.au, .ca, .mn)• Educational (.edu)• Organizations (.org)

• Business (.com)• Government (.gov)• Military (.mil)


Internet Service Providers

• Internet service provider (ISP): any company that provides individuals or organizations with access to the Internet

• Most charge a monthly fee

• Many ISPs and online services offer broadband Internet access through digital subscriber lines (DSLs), cable, or satellite transmission


The World Wide Web

• The Web, WWW, or W3

• A menu-based system that uses the client/server model

• Organizes Internet resources throughout the world into a series of menu pages, or screens, that appear on your computer

• Hypermedia: tools that connect the data on Web pages, allowing users to access topics in whatever order they want


The World Wide Web (continued)

• Hypertext Markup Language (HTML): the standard page description language for Web pages

• HTML tags: codes that let the Web browser know how to format text - as a heading, as a list, or as body text - and whether images, sound, and other elements should be inserted


The World Wide Web (continued)

Figure 4.13: Sample Hypertext Markup Language


Web Browsers

• Web browser: software that creates a unique, hypermedia-based menu on a computer screen, providing a graphical interface to the Web

• The menu consists of graphics, titles, and text with hypertext links

• Popular Web browsers: Microsoft Internet Explorer, Netscape Navigator, Mozilla Firefox, Apple Computer’s Safari


Search Engines and Web Research

Search engine: Web search tool– Examples: Yahoo.com, Google.com

• Most search engines are free

• Searches can use words, such as AND and OR to refine the search

Google Basics• http://www.google.com/intl/en/help/basics.html

Google Advanced Operators• http://www.google.com/intl/en/help/refinesearch.html

http://www.google.com/intl/en/help/basics.html

http://www.google.com/intl/en/help/refinesearch.html

Search Engines and Web Research (continued)

Meta-search engine: submits keywords to several individual search engines and returns results from all these search engines

http://www.dogpile.com/


http://www.dogpile.com/


Search Engines and Web Research (continued)

Table 4.10 Popular Search Engines


Web Programming Languages

• Java– An object-oriented programming language from Sun

Microsystems based on C++– Allows small programs (applets) to be embedded

within an HTML document


Internet and Web Applications: E-Mail, Instant Messaging, and Push

Technology• E-mail is no longer limited to simple text messages

– Sound and images can be embedded in messages– Files that contain text documents, spreadsheets,

graphs, or executable programs can be attached

• Instant messaging: allows two or more individuals to communicate online using the Internet– Push technology (send information automatically to a

user rather than “on request”)


Internet Phone and Videoconferencing Services

• Internet phone service enables you to communicate with others around the world– Relatively inexpensive– Useful for international calls– Ability to keep your phone number when you move

to another location

• Internet videoconferencing– Supports both voice and visual communications


Shopping on the Web

• Shopping on the Web for books, clothes, cars, medications, and even medical advice can be convenient, easy, and cost effective– http://www.webmd.com/

• Bot: software tool that searches the Web for information, products, or prices– http://www.pricegrabber.com/

http://www.webmd.com/

http://www.pricegrabber.com/


Web Auctions

• Web auction: Internet site that matches buyers and sellers– eBay is one of the most popular auction sites

• Traditional companies are starting their own auction sites


Music, Radio, Video, and TV on the Internet

• Music, radio, and video are hot growth areas on the Internet

• Audio and video programs can be played on the Internet, or files can be downloaded for later use


Intranets and Extranets

• Intranet– Internal corporate network built using Internet and

World Wide Web standards and products– Used by employees to have ready access to

corporate information– Reduces need for paper


Intranets and Extranets (continued)

• Extranet– A network based on Web technologies that links

selected resources of a company’s intranet with its customers, suppliers, or other business partners

• Virtual Private Network (VPN): secure connection between two points across the Internet

Documents

Fundamentals of Information Systems Fourth Edition Chapter 4 Telecommunications, the Internet, Intranets, and Extranets