CHAPTER 7 "Telecommunications, The Internet, and Wireless Technology"
7.1 Telecommunications and Networking in Today's Business World
Today you and your employees use computers and e-mail, the
Internet, cell phones, and mobile computers connected to wireless networks for
the business purpose. Networking and the Internet are now nearly synonymous
with doing business.
Networking and Communication Trends
Firms in the past used two fundamentally different types of
networks: telephone networks and computer networks. Thanks to continuing
telecommunications deregulation and information technology innovation,
telephone and computer networks are converging into a single digital network
using shared Internet-based standards and equipment. Both voice and data
communication networks have also become more powerful (faster), more portable (smaller
and mobile), and less expensive.
What is A Computer Network?
A network consists of two or more connected computers. Each
computer on the network contains a network interface device called a network interface card (NIC). The network operating system
(NOS) routes and manages
communications on the network and coordinates network resources.
Networks in Large Companies
The network we’ve just described might be suitable for a small
business. But what about large companies with many different locations and
thousands of employees? The network infrastructure for a large corporation
consists of a large number of these small local area networks linked to other
local area networks and to firmwide corporate networks.
Key Digital Networking Technologies
Contemporary digital networks and the Internet are based on three
key technologies: client/server computing, the use of packet switching, and the
development of widely used communications standards for linking disparate
networks and computers.
Client/Server Computing
Client/server computing is a distributed computing model in which some
of the processing power is located within small, inexpensive client computers,
and resides literally on desktops, laptops, or in handheld devices.
Packet Switching
Packet switching is
a method of slicing digital messages into parcels called packets, sending the
packets along different communication paths as they become available, and then
reassembling the packets once they arrive at their destinations.
TCP/IP and Connectivity
In the past, many diverse proprietary and incompatible protocols
often forced business firms to purchase computing and communications equipment
from a single vendor. But today, corporate networks are increasingly using a
single, common, worldwide standard called Transmission Control Protocol/Internet Protocol (TCP/IP).
7.2 Communications Networks
Signals: Digital vs. Analog
There are two ways to communicate a message in a network: either
using an analog signal or a digital signal. An analog signal is represented by a continuous waveform that passes through a
communications medium and has been used for voice communication. A digital signal is a discrete, binary waveform, rather than a continuous waveform.
Digital signals communicate information as strings of two discrete states: one
bit and zero bits, which are represented as on-off electrical pulses.
Types of Networks
Local Area Networks
A local area network (LAN) is designed to connect personal computers and other digital
devices
within a half-mile or 500-meter radius.
Metropolitan and Wide Area Networks
Wide area networks (WANs) span
broad geographical distances—entire regions, states, continents, or the entire
globe. The most universal and powerful WAN is the Internet. A metropolitan area network (MAN) is a network that spans a metropolitan area, usually a city and
its major suburbs. Its geographic scope falls between a WAN and a LAN.
Physical Transmission Media
Networks use different kinds of physical transmission media:
Twisted Wire
Twisted wire consists of
strands of copper wire twisted in pairs and is an older type of transmission
medium. Twisted-pair cabling is limited to a maximum recommended run of 100
meters (328 feet).
Coaxial Cable
Coaxial cable, similar
to that used for cable television, consists of thickly insulated copper wire
that can transmit a larger volume of data than twisted wire.
Fiber Optics and Optical Networks
Fiber-optic cable consists
of bound strands of clear glass fiber, each the thickness of a human hair.
Fiber-optic cable is considerably faster, lighter, and more
durable than wire media, and is well suited to systems requiring transfers of
large volumes of data. However, fiber-optic cable is more expensive than other
physical transmission media and harder to install.
Wireless Transmission Media
Wireless transmission is based on radio signals of various
frequencies. There are three kinds of wireless networks used by computers:
microwave, cellular, and Wi-Fi.
7.3 The Global Internet
What Is The Internet?
The Internet is the world’s largest implementation of
client/server computing and internetworking, linking millions of individual
networks all over the world. An Internet
service provider (ISP) is a
commercial organization with a permanent connection to the Internet that sells
temporary connections to retail subscribers.
Internet Addressing and Architecture
Every computer on the Internet is assigned a unique Internet Protocol (IP) address, which currently is a 32-bit number represented by four strings
of numbers ranging from 0 to 255 separated by periods.
The Domain Name System
Because it would be incredibly difficult for Internet users to
remember strings of 12 numbers, the Domain
Name System (DNS) converts domain names to IP addresses.
Internet Architecture and Governance
The Internet backbone connects to regional networks, which in turn
provide access to Internet service providers, large firms, and government
institutions. Network access points (NAPs) and metropolitan area exchanges
(MAEs) are hubs where the backbone intersects regional and local networks and where
backbone owners connect with one another.
The Future Internet: IPv6 and Internet2
The Internet was not originally designed to handle the
transmission of massive quantities of data and billions of users. Under development
is a new version of the IP addressing schema called Internet Protocol version 6 (IPv6), which contains 128-bit addresses (2 to the power of 128), or more
than a quadrillion possible unique addresses. Internet2 and
Next-Generation Internet (NGI) are consortia representing 200 universities,
private businesses, and government agencies in the United States that are
working on a new, robust, high-bandwidth version of the Internet.
Internet Services and Communications Tools
The Internet is based on client/server technology. A client uses
the Internet to request information from a particular Web server on a distant
computer, and the server sends the requested information back to the client
over the Internet.
Internet Services
A client computer connecting to the Internet has access to a
variety of services. These services include e-mail, electronic discussion
groups, chatting and instant messaging, Telnet, File Transfer Protocol (FTP), and the Web.
Voice over IP
Voice over IP (VoIP) technology
delivers voice information in digital form using packet switching, avoiding the
tolls charged by local and long-distance telephone networks
Unified Communications
Unified communications integrates
disparate channels for voice communications, data communications, instant
messaging, e-mail, and electronic conferencing into a single experience where
users can seamlessly switch back and forth between different communication
modes.
Virtual Private Networks
A virtual private network
(VPN) is a secure, encrypted,
private network that has been configured within a public network to take
advantage of the economies of scale and management facilities of large
networks, such as the Internet.
The Web
Web site is a
collection of Web pages linked to a home page. Web pages are based on a
standard Hypertext Markup Language (HTML), which formats documents and
incorporates dynamic links to other documents and pictures stored in the same
or remote computers. Web browser software operating your computer can request
Web pages stored on an Internet host server using the Hypertext Transfer Protocol (HTTP).
Web Servers
A Web server is software for locating and managing stored Web
pages. The most common Web server in use today is Apache HTTP Server, which controls
54 percent of the market.
Searching for Information on the Web
Search Engines Obviously,
with so many Web pages, finding specific Web pages that can help you or your
business, nearly instantly, is an important problem. Search engines attempt
to solve the problem of finding useful information on the Web nearly instantly,
and, arguably, they are the “killer app” of the Internet era.
Web 2.0
Today’s Web sites don’t just contain static content—they enable
people to collaborate, share information, and create new services and content
online. These second-generation interactive Internet-based services are
referred to as Web 2.0. Web 2.0 has four defining features: interactivity, real-time
user control, social participation (sharing), and user-generated content.
Web 3.0: The Future Web
Web 1.0 solved the problem of obtaining access to information. Web
2.0 solved the problem of sharing that information with others, and building
new Web experiences. Web 3.0 is the promise of a future Web where all this digital information,
all these contacts, can be woven together into a single meaningful experience.
7.4 The Wireless Revolution
Wireless communication helps businesses more easily stay in touch
with customers, suppliers, and employees and provides more flexible
arrangements for organizing work.
Cellular Systems
Earlier generations of cellular systems were designed primarily
for voice and limited data transmission in the form of short text messages.
Wireless carriers now offer more powerful cellular networks called third-generation
or 3G networks, with transmission speeds ranging from 144 Kbps for
mobile users in, say, a car, to more than 2 Mbps for stationary users. The next evolution in wireless communication,
called 4G networks, is entirely packet switched and capable of 100 Mbps transmission
speed (which can reach 1 Gbps under optimal conditions), with premium quality
and high security.
Wireless Computer Networks and Internet Access
An array of technologies provide high-speed wireless access to the
Internet for PCs and other wireless handheld devices as well as for cell
phones. These new high-speed services have extended Internet access to numerous
locations that could not be covered by traditional wired Internet services.
Bluetooth
Bluetooth is the
popular name for the 802.15 wireless networking standard, which is useful for
creating small personal area networks
(PANs).
Wi-Fi and Wireless Internet Access
The 802.11 set of standards for wireless LANs and wireless
Internet access is also known as Wi-Fi. Hotspots typically consist of one or more access points providing wireless Internet
access in a public place. Businesses of all sizes are using Wi-Fi networks to
provide low-cost wireless
LANs and Internet access. Wi-Fi hotspots can be found in hotels,
airport lounges, libraries, cafes, and college campuses to provide mobile
access to the Internet.
WiMax
WiMax, which stands for Worldwide
Interoperability for Microwave Access, is the popular term for IEEE Standard
802.16. It has a wireless access range of up to 31 miles and transmission speed
of up to 75 Mbps.
RFID and Wireless Sensor Networks
Radio Frequency Identification (RFID)
Radio frequency identification (RFID) systems provide a powerful technology for tracking the movement of
goods throughout the supply chain. RFID systems use tiny tags with embedded
microchips containing data about an item and its location to transmit radio
signals over a short distance to RFID readers.
Wireless Sensor Networks
Wireless sensor networks (WSNs) are networks of interconnected wireless devices that are embedded
into the physical environment to provide measurements of many points over large
spaces.
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source: "Management Information System" e-book, 12th edition, written by Kenneth C. Laudon and Jane P. Laudon.