7 - Telecom, internet & wireless tech

Chapter 7

Telecommunications, the
Internet, and Wireless
Technology

Management Information Systems
Chapter 7 Telecommunications, the Internet, and Wireless Technology

LEARNING OBJECTIVES

• Identify the principal components of telecommunications
networks and key networking technologies.

• Describe the main telecommunications transmission media
and types of networks.

• Explain how the Internet and Internet technology work and
how they support communication and e-business.

• Identify the principal technologies and standards for
wireless networking, communication, and Internet access.

• Assess the value to business of radio frequency
identification (RFID) and wireless sensor networks.


Virgin Megastores Keeps Spinning with Unified Communications

• Problem: 1400 employees in 11 retail locations; slow
resolutions of business issues because of cost of
conference calls
• Solutions: Implement unified communications to
integrate voice mail, e-mail, conference calling,
instant messaging
• Microsoft’s Office Communication Server, Office
Communicator, RoundTable conferencing and
collaboration tools
• Demonstrates IT’s role in hastening communication
and flow of information


Telecommunications and Networking in Today’s Business World

• Networking and communication trends
• Convergence:
• Telephone networks and computer networks converging
into single digital network using Internet standards
• Cable companies providing voice service
• Broadband:
• More than 60% of U.S. Internet users have broadband
access
• Broadband wireless:
• Voice and data communication as well as Internet access
are increasingly taking place over broadband wireless
platforms

Components of data
communication

What is Data ?

• Data is a collection of facts, such as values or measurements.

• It can be numbers, words, measurements, observations or even
just descriptions of things.

• Data can exist in a variety of forms -- as numbers or text on
pieces of paper, as bits and bytes stored in electronic memory,
or as facts stored in a person's mind.

• Data is the plural of datum, a single piece of information.

 Data communication is the transfer of information between two points, either
via an analogue (sine wave) electrical signal or digital (binary ) signal via
electrical pulses or optically via light pulses.

 High speed data exchange between computers and/or other
electronic devices via cable or wireless.

Data Transmission Modes
There are three modes of transmitting data from
one point to another. These are :

Receiv
• Simplex Sender
er
Sender Receiver
• Half-duplex (or OR (or
Receiver) Sender)
• Full-duplex
Sender Receiver
(and AND (and
Receiver) Sender)

COMPONENTS

The main components of data communication system are:

• Message

• Sender

• Receiver

• Medium

MESSAGE
• Message may exist in several different forms. It
could be sound, light, picture, text, video etc.

• A message is information which is sent from
a source to a receiver.

Transmitter

A transmitter is the agent, which could be a
human or a machine, that actually wishes to
transmit the data/ information to a recipient is
called the transmitter or sender.

Receiver

Receiver is the component that collects the coded message
from the communication channel. This piece of data is still not
in the form of the original message.

Medium

Once signal corresponding to the message is obtained, an end-
to-end medium is required through which the signal may travel
from the sender to the other end.

Transmission Medium

• Provides the path for data communication.
• Allows a bit stream to be transported from
one machine to another.

Twisted Pair Cable
Coaxial Cable
Optical Fiber Cable

MEDIA ADVANTAGES DISADVANTAGES

Twisted Pair Inexpensive, well Sensitive to noise,
Cables established. short distances,
security hazard
because of easy
interception.

Coaxial Cable High bandwidth, long Security is better in
distances. comparison to twisted
pair cable.

Optical Fiber Very high bandwidth, long Connections Cost.
Cable distances, high security,
small size.



• What is a computer network?
• Two or more connected computers
• Major components in simple network
• Client computer
• Server computer
• Network interfaces (NICs)
• Connection medium
• Network operating system
• Hub or switch
• Router



Components of a Simple Computer Network

Illustrated here is a very simple computer network, consisting of
computers, a network operating system residing on a dedicated
server computer, cabling (wiring) connecting the devices, network
interface cards (NIC), switches, and a router.

Figure 7-1

What is a Computer Network?
A network is a collection of computers, printers, routers, switches, and other
devices that are able to communicate with each other over some
transmission media.

Types of Networks
There are two basic types of networks currently in existence:
A Local Area Network (LAN)
A Wide Area Network (WAN)

Local Area
Networks A Local Area Network (LAN) is a group of computers and
(LAN) network communication devices within a limited geographic area,
such as an office building. No third party involvement here.
They are characterized by the following:
• High data transfer speeds
• Generally less expensive technologies
• Limited geographic area

Wide Area
Networks
(WAN) A Wide Area Network (WAN) interconnects LANs. It is not
restricted to a particular geographic area and may be
interconnected around the world. Third party network is involved.
They are characterized by the following:
• Multiple interconnected LANs
• Generally more expensive technology
• More sophisticated to implement than LANs
• Exist in an unlimited geographic area
• Less error resistance due to transmission travel distances

Common LAN Topologies
Bus Architecture In a bus topology:
• a single cable connects each
workstation in a linear, daisy-chained
fashion.

•signals are broadcasted to all
stations, but stations only act on the
frames addressed to them.

Ring Architecture
•In a ring topology:

•Unidirectional links connect the
transmit side of one device to the
receive side of another device.
•Devices transmit frames to the next
device (downstream member) in the
ring.

Star Topology

In a star topology, each station is connected to a central
hub or concentrator that functions as a multi-port
repeater. Each station broadcasts to all of the devices
connected to the hub. Physical LAN topologies are
usually characterized as either bus or ring.

LAN Transmission Methods
LAN transmission methods fall into 3 main categories:
• Unicast transmission
• Multicast transmission
• Broadcast transmission

Unicast Transmission
In unicast transmissions, a single data packet is sent from a source to a
single destination on the network.

Unicast Process

• The source addresses
the packet with the
destination address.
• The packet is sent into
the network.
• The network delivers the
packet to the destination.

Multicast Transmission

In multicast transmissions, a single data packet is copied and sent to
specific destinations on the network

Multicast Process

• The source addresses the packet
using a multicast address.
• The packet is sent into the
network.
• The network copies the packet.
• A copy is delivered to each
destination that is included in the
multicast address.

Broadcast Tranmission
In Broadcast transmissions, a single data packet is copied and sent to all
destinations on the network

Broadcast Process

• The source addresses the packet with the broadcast address.
• The packet is sent into the network.
• The network copies the packet.
• The packet copies are delivered to all destinations on the
network.

Uses of Computer Networks
• Resource Sharing: Many organizations have large number of
substantial computers in operation often located far apart. Let
us consider an example, a company having many factories
situated at different locations. A computer at each location
(that is in each factory) keeps the track of inventories, monitor
productivity and do the local pay roll. Initially each of these
computers may have worked in isolation from each other, but
at some point, the management may have decided to connect
these computers to be able to extract and correlate the
information of the entire company.

The issue here is resource sharing. Its goal is to make all the
programs, equipments, especially data available to anyone on
the network irrespective of the location of the resource and
the user.

• High Reliability: The second goal or use of
networking in companies is to high reliability by
having alternative sources of supply. For example all
the files can be replicated on two or more machines,
so that in case one of them is not available (due to
hardware failure), other copies can be used. This
feature is used in financial institutions.

• Scalability: Another goal is scalability. Scalability is
the ability to increase the system performance
gradually as the workload grows, by just adding more
processors.

• Saving Money: The third goal is to save money. Small
computers often have better price/performance ratio
than the larger ones. Mainframe (room-size) computers
are roughly ten times faster than the personal
computers, but are a thousand times costly. This
imbalance caused the system designers to design a
system consisting of personal computers, one per user,
with data kept on one or more shared file server
machines. In this model the user are called the clients
and this whole arrangement is known as the client-server
model.

In client-server model, the communication generally
takes the form of a request message from a client to the
receiver asking for some work to be done. Server does
the work and sends back the reply.

• Access to Remote Information: Access to remote
information occurs in many forms. One of the areas
where it is happening is access to the financial
institutions. Many people pay their bills, manage
bank accounts and handle investments electronically.
Home shopping is also becoming popular these days.

Another application that falls under this category is
the access to information systems like World Wide
Web which contains information about art, business,
history, government, geography, economics and
several other topics.

All the above applications involve the interaction
between the user and a remote database.

• Person to Person Communication: Electronic Mail
popularly known as email is widely used by millions
of people to send text messages, photographs audio
as well as video to other people or group of people.
This application belongs to person to person
communication category.

Videoconferencing is also becoming popular these
days. This technology makes it possible to have
virtual meetings among far flung people. It is also a
type of person to person communication.

• Interactive Entertainment: These days we can
see many live programmes and shows. The
best thing is that we can interact with them by
participating in the quizzes and the contests
organized by them.
• File sharing: Have you ever needed to access a
file stored on another computer? A network
makes it easy for everyone to access the same
file and prevents people from accidentally
creating different versions.

• Printer sharing: If you use a computer, chances are
you also use a printer. With a network, several
computers can share the same printer. Although you
might need a more expensive printer to handle the
added workload, it's still cheaper to use a network
printer than to connect a separate printer to every
computer in your office.

• Communication and collaboration: It's hard for
people to work together if no one knows what
anyone else is doing. A network allows employees to
share files, view other people's work, and exchange
ideas more efficiently. In a larger office, you can use
e-mail and instant messaging tools to communicate
quickly and to store messages for future reference.

• Organization: A variety of scheduling software
is available that makes it possible to arrange
meetings without constantly checking
everyone's schedules. This software usually
includes other helpful features, such as shared
address books and to-do lists.

Networking Hardware
• NICs
• Repeaters and Hubs
• Switches
• Routers
• Bridges
• Brouter
• Gateway
• Modems
• ISDN Adaptors
• CSU/DSU
• Network Example

NICs
• Network interface cards (also called NICs, network adapters,
LAN Card or network cards) are connectivity devices that
enable a workstation, server, printer, or other node to
receive and transmit data over the network media.
• Nearly all NICs contain a data transceiver, the device that
transmits and receives data signals.
• NICs belong to both the Physical layer and Data Link layer of
the OSI Model, because they apply data signals to the wire
and assemble or disassemble data frames.
• In addition, they perform the routines that determine which
node has the right to transmit data over a network at any
given instant

Repeaters and Hubs
• Repeaters operate in the Physical layer of the OSI Model
and, therefore, have no means to interpret the data they
retransmit.
• They simply regenerate a signal over an entire segment.
• A repeater contains one input port and one output port,
so it is capable only of receiving and repeating a data
stream
• Repeaters are suited only to bus topology networks
• The advantage to using a repeater is that it allows you to
extend a network inexpensively

Repeaters and Hubs
• A hub is a repeater with more than one output port.
• A hub typically contains multiple data ports into
which the patch cables for network nodes are
connected.
• A hub accepts signals from a transmitting node and
repeats those signals to all other connected nodes in
a broadcast fashion

Switches

• Switches are connectivity devices that
subdivide a network into smaller logical
pieces, or segments.
• Switches operate at the Data Link layer of the
OSI Model, while more modern switches can
operate at Layer 3 or even Layer 4.
• Switches interpret MAC address information

• Because they have multiple ports, switches can
make better use of limited bandwidth.
• Each device connected to a switch effectively
receives its own dedicated channel to the switch.
• From the Ethernet perspective, each dedicated
channel represents a collision domain.
• Because a switch limits the number of devices in a
collision domain, it limits the potential for collisions.
• By their nature switches provide better security than
many other devices because they isolate one
device's traffic from other device’s traffic

• Connecting a workstation to a switch

• A switch on a small network

Switches Contd….
• Switches differ in the method of switching they use:
1. Cut-through mode
2. Store and forward mode

Cut-Through Mode

• A switch running in cut-through mode reads a frame's header
and decides where to forward the data before it receives the
entire packet.
• What if the frame becomes corrupt? Because the cut-
through mode does not allow the switch to read the frame
check sequence (FCS) before it begins transmitting, it can't
verify data integrity in that way.

Store and Forward Mode

• In store and forward mode, a switch reads the entire
data frame into its memory and checks it for
accuracy before transmitting the information.
• Although this method is more time-consuming than
the cut- through method, it allows store and forward
switches to transmit data more accurately.
• Store and forward mode switches are more
appropriate for larger LAN environments, because
they do not propagate data errors.

Routers
• A router is a multiport connectivity device that
directs data between nodes on a network.
• Routers can integrate LANs and WANs running at
different transmission speeds and using a variety of
protocols.
• When a router receives an incoming packet, it reads
the packet's logical addressing information.
– Based on this, it determines to which network the packet
must be delivered.
– Then it determines the shortest path to that network.
– Finally it forwards the packet to the next hop in that path.

• A router's strength lies in its intelligence.
• Not only can routers keep track of the
locations of certain nodes on the network, as
switches can, but they can also determine the
shortest, fastest path between two nodes.
• For this reason, and because they can connect
dissimilar network types, routers are
powerful, indispensable devices on large
LANs and WANs.
• The Internet, for example, relies on a
multitude of routers across the world

• A typical router has an internal processor, an operating
system, memory, input and output jacks for different types of
network connectors (depending on the network type), and,
usually, a management console interface.

Hub versus Switch

• Hub provide connection to all ports (i.e. in one
port and out all other ports).
– Passive hub – no signal regeneration
– Active hub – provide signal regeneration
• Switch direct the message from appropriate
port (directs a message from the input port to
the desired output port).
– More expensive but better bandwidth utilization

Bridge

• Connects two LAN segments to make one larger
continuous LAN
• Filters LAN traffic to keep local traffic.
• Allows connectivity to other parts of the LAN
• Simple to install and manage—costs less than router
• Checks MAC address to make forwarding decisions
• Considered layer 2 device

Bridge – Access Point (WLAN)

Brouter

• Network bridge and router combined
together to form a device known as
brouter.

Gateway
• A gateway is a network point that acts as an entrance to
another network. On the Internet, a node or stopping point
can be either a gateway node or a host (end-point) node. Both
the computers of Internet users and the computers that serve
pages to users are host nodes, while the nodes that connect
the networks in between are gateways. For example, the
computers that control traffic between company networks or
the computers used by internet service providers (ISPs) to
connect users to the internet are gateway nodes.
• In the network for an enterprise, a computer server acting as
a gateway node is often also acting as a proxy server and a
firewall server. A gateway is often associated with both a
router, which knows where to direct a given packet of data
that arrives at the gateway, and a switch, which furnishes the
actual path in and out of the gateway for a given packet.

Modem

• Allows modems of different vendors to
operate together
• Define How modems operate:
– Modulation techniques
– Data compression technique
– Error detection strategy
– Parallel to Serial and vice versa

• Analog
– Infinite number of levels
– Conform to voice pattern
– Times from highest to lowest and back to the
highest point in one second is the frequency
– Can be transmitted over long distance

• Digital
– Only two levels (high and low)
– Conforms to how computers operate
– Cannot transmitted over long distance

ISDN Adaptors

• ISDN (Integrated Services Digital Network) is a data
communication method and it is used over the
regular telephone lines. To use the ISDN lines, you
need to install add-on adapters known as ISDN
terminal adapters. ISDN Terminal Adapter works like
a digital modem i.e. it converts the signals from
digital to analog and vice versa. ISDN Terminal
adapter is plugged into the serial port of the
system. Some ISDN adapters have the feature of
switching between digital and analog modes.

CSU/DSU
• CSU/DSU stands for channel service unit and data
service unit. CSU is used to connect a terminal to a
digital line. DSU is used to perform the protective
and diagnostic functions of the telecommunication
line. CSU/DSU is a network device of the size of an
external modem. The Channel service unit receives
and transmits the signals from the wide area
network line. CSU/DSU are two separate devices and
they are sometimes used in conjunction with the T1
LAN cards.

Network Software
• Network Software is a set of primitives that define the protocol
between two machines. The network software resolves an ambiguity
among different types of network making it possible for all the
machines in the network to connect and communicate with one
another and share information.

• Network software is the information, data or programming used to
make it possible for computers to communicate or connect to one
another.

• Network software is used to efficiently share information among
computers. It encloses the information to be sent in a “package” that
contains a “header” and a “trailer”. The header and trailer contain
information for the receiving computer, such as the address of that
computer and how the information package is coded. Information is
transferred between computers as either electrical signals in electric
wires, as light signals in fiber-optic cables, or as electromagnetic waves
through space.

Networks provide computer users a
convenient way to transfer files across
data connections. Secured networks
require a user name and password in
order to connect your computer to the
network. Unsecured networks do not
need any authentication. All types of
networks need software to interface with
the network and begin communication
and data transfer.

• Home Software : Setting up a network using the Cisco
software Network Magic Pro is easy; the software was
programmed with novice computer users in mind. Tasks such
as creating secured Internet connections, sharing digital
devices such as cameras and printers and monitoring Web
access are all controlled through the software's main
interface. This software is ideal for entry-level computer
users.

• Free Software : Spiceworks provides a budget-friendly option
for individuals who want a network management software
package. The software is free and offers many of the same
features as other software packages available for sale. This
software package was intended to be used within small to
medium sized businesses. The few of the key features are the
ability to inventory everything on your network, run an IT
Helpdesk and Map the Network.

• Monitoring Tools : Networks are often damaged from burnt
power supplies, servers crashing, low bandwidth and even
attacks from computer hackers. Computer hackers are experts
in network administration, but the appropriate software will
stop hackers dead in their tracks. The software Monitor Tools
provides a central location to monitor and maintain all these
potential trouble spots. The software will tell you of possible
system issues and provide quick suggestions for the resolution
of each problem as it arises.
• Application Performance : Network administrators are
sometimes charged with the sole task of monitoring
application performance, for example, making sure that files
are sent immediately and are successfully delivered on the
receiving end. Orion APM is a software package that focuses
exclusively on application monitoring, ensuring all network
systems are running as quickly as possible.

• Warning : Choosing to set up a security system for
your wireless network is a decision to be taken
seriously. A wireless network places your computer
files at the fingertips of anyone within the broadcast
range of your wireless router. Personal information
such as Social Security numbers and credit cards
should always be stored behind the protection of
certified network security software. Once your
network is set up, and your files are secured, routine
backups of any important files should be created
onto hard drives, DVDs or other external storage
medium. The only way to be absolutely certain your
files are safe is to have a hard copy stored outside
the network; if the network fails and data is lost, you
will be certain your important files are still safe.

Network Model Overview
In order for a computer to send information to another computer, and for that
computer to receive and understand the information, there has to exist a set
of rules or standards for this communication process. These standards
ensure that varying devices and products can communicate with each other
over any network. This set of standards is called a model.
Network Model Advantages
This division provides advantages for the network design, architecture and
implementation. These include:
Reduces complexity - by dividing the processes into groups, or layers,
implementation of network architecture is less complex
•Provides compatibility - standardized interfaces allow for "plug-and-play"
compatibility and multi-vendor integration
•Facilitates modularization - developers "swap" out new technologies at
each layer keeping the integrity of the network architecture
•Accelerates evolution of technology - developers focus on technology at
one layer while preventing the changes from affecting another layer
•Simplifies learning - processes broken up into groups divides the
complexities into smaller, manageable chunks



• Networks in large companies
• Components can include:
• Hundreds of local area networks (LANs) linked to firmwide
corporate network
• Various powerful servers
• Web site
• Corporate intranet, extranet
• Backend systems
• Mobile wireless LANs (Wi-Fi networks)
• Videoconferencing system
• Telephone network
• Wireless cell phones



Corporate Network Infrastructure

Figure 7-2
Today’s corporate network
infrastructure is a collection of
many different networks from the
public switched telephone
network, to the Internet, to
corporate local area networks
linking workgroups, departments,
or office floors.



• Key digital networking technologies
• Client/server computing
• Distributed computing model
• Clients linked through network controlled by network
server computer
• Server sets rules of communication for network and
provides every client with an address so others can find it
on the network
• Has largely replaced centralized mainframe computing
• The Internet: Largest implementation of client/server
computing



• Packet switching
• Method of slicing digital messages into parcels (packets),
sending packets along different communication paths as
they become available, and then reassembling packets at
destination
• Previous circuit-switched networks required assembly of
complete point-to-point circuit
• Packet switching more efficient use of network’s
communications capacity



Packet-Switched Networks and Packet Communications

Figure 7-3
Data are grouped into small packets,
which are transmitted independently over
various Communications channels and
reassembled at their final destination.



• TCP/IP and connectivity
• Connectivity between computers enabled by protocols
• Protocols: Rules that govern transmission of information
between two points
• Transmission Control Protocol/Internet Protocol
(TCP/IP)
• Common worldwide standard that is basis for Internet
• Department of Defense reference model for TCP/IP
• Four layers
• Application layer
• Transport layer
• Internet layer
• Network interface layer



The Transmission Control Protocol/Internet
Protocol (TCP/IP) Reference Model

Figure 7-4
This figure illustrates the four layers of the
TCP/IP reference model for communications.

OSI Network Model
There are 7 layers in the OSI
model. Each layer is
responsible for a particular
aspect of data communication.
For example, one layer may be
responsible for establishing
connections between devices,
while another layer may be
responsible for error checking
during transfer.
The layers of the OSI model are divided into two groups: the upper layer
and lower layer. The upper layers focus on user applications and how files
are represented on the computers prior to transport. For the most part,
network engineers are more concerned with the lower layers. It's the lower
layers that concentrate on how the communication across a network
actually occurs.

ALL People Seem to Need Data Processing (Layer 7 to 1)
Please Do Not Take Sausage Pizzas Away (Layer 1 to 7)

The Application Layer
The Application Layer is the highest layer in the
protocol stack and the layer responsible for
introducing data into the OSI stack. In it resides the
protocols for user applications that incorporate the
components of network applications.
Classification of Applications
Computer applications
Network applications
Internetwork applications

Examples: Telnet, FTP, HTTP, WWW Browsers, NFS,
SMTP, POP, TFTP .

Presentation Layer

The Presentation Layer manipulates the
representation of data for transfer to applications on
different devices.

The Presentation Layer is responsible for the
following services:
• Data representation
• Data security
• Data compression

Data Representation

Session Layer

The Session Layer establishes, manages, and
terminates sessions (different from connections) between
applications as they interact on different hosts on a
network.
Its main job is to coordinate the service requests and
responses between different hosts for applications.
Examples: NFS, SQL, RPC, ASP

Three different communication modes exists for data
transfer within a session connection:
• Single-duplex

• Half-duplex

• Full-duplex.

Figure 2.1 Tasks involved in sending a letter

2.80

What do the 7 layers really do?


Communications Networks

• Signals: digital vs. analog
• Modem: Translates digital signals into analog form
• Types of networks
• Local-area networks (LANs)
• Client/server or peer-to-peer
• Ethernet – physical network standard
• Topologies: star, bus, ring

• Campus-area networks (CANs)

• Wide-area networks (WANs)

• Metropolitan-area networks (MANs)



Functions of the Modem

A modem is a device that translates digital signals from a computer into analog form so that they can be transmitted over
analog telephone lines. The modem also translates analog signals back into digital form for the receiving computer.

Figure 7-5



Network Topologies

Figure 7-6
The three basic network
topologies are the bus,
star, and ring.



• Physical transmission media
• Twisted wire (modems)
• Coaxial cable
• Fiber optics and optical networks
• Wireless transmission media and devices
• Microwave
• Satellites
• Cellular telephones
• Transmission speed
• Hertz
• Bandwidth



BP Amoco’s Satellite Transmission System

Figure 7-7
Communication satellites
help BP Amoco transfer
seismic data between oil
exploration ships and
research centers in the
United States.


The Global Internet

• What is the Internet?
• Connecting to the Internet
• Internet service providers (ISPs)
• Services
• DSL, cable, satellite, T lines (T1, T3)

• Internet addressing and architecture
• IP addresses
• The domain name system
• Hierarchical structure
• Top-level domains


The Global Internet

The Domain Name System

Figure 7-8
The Domain Name System is a
hierarchical system with a root
domain, top-level domains,
second-level domains, and host
computers at the third level.


The Global Internet

• Internet Architecture
• Trunk lines (backbone networks)
• Regional networks
• ISPs
• Internet Governance
• No formal management
• Policies established by professional, government organizations
• IAB, ICANN, W3C
• The Future Internet
• IPv6
• Internet2, NGI


The Global Internet

Internet Network Architecture

Figure 7-9
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 Wireless Revolution

Should Network Neutrality Continue?
• Read the Interactive Session: Organization and then
discuss the following questions:
• What is network neutrality? Why has the Internet operated
under net neutrality up to this point in time?
• Who’s in favor of network neutrality? Who’s opposed?
Why?
• What would be the impact on individual users, businesses,
and government if Internet providers switched to a tiered
service model?
• Are you in favor of legislation enforcing network
neutrality? Why or why not?


The Global Internet

• Internet services
• E-mail
• Chatting and instant messaging
• Newsgroups
• Telnet
• File Transfer Protocol (FTP)
• World Wide Web
• Voice over IP (VoIP)
• Unified communications
• Virtual private networks (VPNs)


The Global Internet

Client/Server Computing on the Internet

Figure 7-10
Client computers running Web
browser and other software can
access an array of services on servers
over the Internet. These services may
all run on a single server or on
multiple specialized servers.


The Global Internet

Monitoring Employees on Networks: Unethical or Good Business?

• Read the Interactive Session: Management and
then discuss the following questions:
• Should managers monitor employee e-mail and Internet
usage? Why or why not?
• Describe an effective e-mail and Web use policy for a
company.


The Global Internet

How Voice over IP Works

An VoIP phone call digitizes and breaks up a voice message into data packets that may travel along different routes before
being reassembled at the final destination. A processor nearest the call’s destination, called a gateway, arranges the packets
in the proper order and directs them to the telephone number of the receiver or the IP address of the receiving computer.

Figure 7-11


The Global Internet

A Virtual Private Network Using the Internet

This VPN is a private network of computers linked using a secure “tunnel” connection over the Internet. It protects data transmitted
over the public Internet by encoding the data and “wrapping” them within the Internet Protocol (IP). By adding a wrapper around a
network message to hide its content, organizations can create a private connection that travels through the public Internet.

Figure 7-12


The Global Internet

• The World Wide Web
• HTML (Hypertext Markup Language):
• Formats documents for display on Web
• Hypertext Transfer Protocol (HTTP):
• Communications standard used for transferring Web
pages
• Uniform resource locators (URLs):
• Addresses of Web pages
• E.g.,
http://www.megacorp.com/content/features/082602.html
• Web servers
• Software for locating and managing Web pages


The Global Internet

• Search engines
• Started in early 1990s as relatively simple software programs
using keyword indexes
• Today, major source of Internet advertising revenue via
search engine marketing, using complex algorithms and
page ranking techniques to locate results
• Sponsored links vs. organic search results
• Shopping bots
• Use intelligent agent software for searching Internet for
shopping information


The Global Internet

How Google Works

Figure 7-13
The Google search engine is
continuously crawling the
Web, indexing the content of
each page, calculating its
popularity, and storing the
pages so that it can respond
quickly to user requests to
see a page. The entire
process takes about one-half
second.


The Global Internet

Major Web Search Engines

Figure 7-14
Google is the most popular search
engine on the Web, handling 56 percent
of all Web searches.


The Global Internet

• Web 2.0
• Second-generation interactive Internet-based services enabling
people to collaborate, share information, and create new
services online
• Cloud computing
• Software mashups and widgets
• Blogs: Chronological, informal Web sites created by
individuals using easy-to-use weblog publishing tools
• RSS (Really Simple Syndication): Syndicates Web content
so aggregator software can pull content for use in another
setting or viewing later
• Wikis: Collaborative Web sites where visitors can add, delete,
or modify content on the site


The Global Internet

• Web 3.0
• Current efforts to make using Web more productive
• Inefficiency of current search engines: Of 330 million
search engine queries daily, how many are fruitful?
• Semantic Web
• Collaborative effort to add layer of meaning on top of
Web, to reduce the amount of human involvement in
searching for and processing Web information
• Other, more modest views of future Web
• Increase in cloud computing, SaaS
• Ubiquitous connectivity between mobile and other
access devices
• Make Web a more seamless experience


The Global Internet

• Intranets
• Use existing network infrastructure with Internet connectivity
standards software developed for the Web
• Create networked applications that can run on many types of
computers
• Protected by firewalls
• Extranets
• Allow authorized vendors and customers access to an internal
intranet
• Used for collaboration
• Also subject to firewall protection



• Wireless devices
• PDAs, BlackBerry, smart phones
• Cellular systems
• Competing standards for cellular service
• United States: CDMA
• Most of rest of world: GSM
• Third-generation (3G) networks
• Higher transmission speeds suitable for broadband Internet
access



• Wireless computer networks and Internet access
• Bluetooth (802.15)
• Links up to 8 devices in 10-m area using low-power, radio-
based communication
• Useful for personal networking (PANs)
• Wi-Fi (802.11)
• Set of standards: 802.11a, 802.11b, 802.11g, 802.11n
• Used for wireless LAN and wireless Internet access
• Use access points: Device with radio receiver/transmitter
for connecting wireless devices to a wired LAN



A Bluetooth Network (PAN)

Figure 7-15
Bluetooth enables a variety
of devices, including cell
phones, PDAs, wireless
keyboards and mice, PCs,
and printers, to interact
wirelessly with each other
within a small 30-foot (10-
meter) area. In addition to
the links shown, Bluetooth
can be used to network
similar devices to send data
from one PC to another, for
example.



An 802.11 Wireless LAN

Figure 7-16
Mobile laptop computers equipped with
wireless network interface cards link to
the wired LAN by communicating with
the access point. The access point uses
radio waves to transmit network signals
from the wired network to the client
adapters, which convert them into data
that the mobile device can understand.
The client adapter then transmits the
data from the mobile device back to the
access point, which forwards the data
to the wired network.



• Wireless computer networks and Internet access
• Wi-Fi (cont.)
• Hotspots: One or more access points in public place to
provide maximum wireless coverage for a specific area
• Weak security features
• WiMax (802.16)
• Wireless access range of 31 miles
• Require WiMax antennas
• Sprint Nextel building WiMax network



• Radio frequency identification (RFID)
• Use tiny tags with embedded microchips containing data
about an item and location, and antenna

• Tags transmit radio signals over short distances to special
RFID readers, which send data over network to computer for
processing

• Active RFID: Tags have batteries, data can be rewritten,
range is hundreds of feet, more expensive

• Passive RFID: Range is shorter, also smaller, less
expensive, powered by radio frequency energy



• Radio frequency identification (RFID)
• Common uses:

• Automated toll-collection

• Tracking goods in a supply chain

• Requires companies to have special hardware and software

• Reduction in cost of tags making RFID viable for many firms



How RFID Works

RFID uses low-powered radio transmitters to
read data stored in a tag at distances ranging
from 1 inch to 100 feet. The reader captures the
data from the tag and sends them over a
network to a host computer for processing.
Figure 7-17



• Wireless sensor networks
• Networks of hundreds or thousands of interconnected wireless
devices embedded into physical environment to provide
measurements of many points over large spaces
• Used to monitor building security, detect hazardous substances
in air, monitor environmental changes, traffic, or military activity
• Devices have built-in processing, storage, and radio frequency
sensors and antennas
• Require low-power, long-lasting batteries and ability to endure in
the field without maintenance



A Wireless Sensor Network

Figure 7-18
The small circles represent
lower-level nodes and the larger
circles represent high-end
nodes. Lower-level nodes
forward data to each other or to
higher-level nodes, which
transmit data more rapidly and
speed up network performance.

7 - Telecom, internet & wireless tech

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