Transcript Technology: Telecommunications and Networks

Mgt 20600:
IT Management & Applications
Telecommuncations and Networks
Tuesday
March 28, 2006
Reminders
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
Reading
– For today
 Fundamentals text, Chapter Four,
Telecommunications chapter
– For next class on April 4th
 Fundamentals text, Chapter Three, Organizing Data
and Information
Homework
– Homework Three
 Networks and Telecommunications
 Due Friday, March 31st
 Will need to use outside resources to answer several
questions
Next week: Databases
Networking and
Telecommunications
 Effective
communications are
essential to organizational success
 Why?
– Business processes are supported by
software that runs over networks
– Must choose right software to support
business, then design the right network
to support the operation of the software
– Processing model will help determine
what kind of network you need
Basic Processing Strategies
 Centralized
processing: all
processing occurs in a single location
or facility
 Decentralized processing:
processing devices are placed at
various remote locations
 Distributed processing: computers
are placed at remote locations but
connected to each other via a
network
Distributed Processing Options

Terminal-to-host: the application and database
reside on one host computer, and the user
interacts with the application and data using a
“dumb” terminal
Distributed Processing Options
File or Application Server: the
application or database reside on the one
host computer, called the file server
Distributed Processing Options
Client/Server
Client:
End-user’s computer
PC, mobile device, thin client
Server: Mid-range computer
Dedicated to special function such as
database server, print server, web
server, application server
Client and server share in processing task
Example, the World Wide Web
Telecommuncations
– 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
Telecommunications and
Networks
Elements of a Telecommunications System
Transmission Media
Wired Transmission Media Types
Wired Media Types
Wireless Transmission
Media Types

Radio Waves
– Bluetooth
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Short distances only
Relatively slow transmission speed
Developed for inter-device communications
– Wi-Fi
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Standard supports up to 54Mbps
Supports longer distances than bluetooth
Infrared
– Signals sent as light waves
– Short distance
– Unobstructed line of sight
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Microwave
–
–
–
–

High frequency radio signal
Capable of high-speed transmission
Unobstructed line of sight
Susceptible to interference
Cellular
Networks
 Computer
network: the
communications media, devices, and
software needed to connect two or
more computer systems or devices
 Network nodes: the computers and
devices on the networks
Network Types
 Personal
area network (PAN)
 Local area network (LAN)
 Metropolitan area network (MAN)
 Wide area network (WAN)
 International network
Network Types
A Typical LAN
Network Types
Is the internet
a wide area
network?
A Wide Area Network
Communications Software and
Protocols

Communications software: software
that provides a number of important
functions in a network, such as error
checking and data security
– Network operating system (NOS)
– Network management software
– Communications protocol: a standard set of
rules that controls a telecommunications
connection
 Example,
TCP/IP protocol that underlies the Internet
The Internet
 Internet:
a collection of
interconnected networks, all freely
exchanging information
 ARPANET
– The ancestor of the Internet
– A project started by the U.S.
Department of Defense (DoD) in 1969
How the Internet Works

Data is passed in chunks called packets
– Internet Protocol (IP):
communications standard that enables
traffic to be routed from one network to
another as needed
– Transmission Control Protocol
(TCP): widely used transport-layer
protocol that is used in combination with
IP by most Internet applications
How the Internet Works
Routing Messages over the Internet
Accessing the Internet
Several Ways to Access the Internet
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
Applications that run over the
Internet
World Wide Web
 Instant Messaging
 Email
 File Transfer Protocol
 Telnet
 All of these are
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– Software applications
– Designed for the internet
– All assume your computer understands TCP/IP
The World Wide Web
Hypertext Transfer Protocol (HTTP):
Protocol that web servers and browsers
use to send requests and information
 Hypertext Markup Language (HTML):
the standard page description language
for Web pages
 Uniform Resource Locator (URL): an
assigned address on the Internet for each
computer

Intranets and Extranets
 Intranet
– Internal corporate network built using
Internet and World Wide Web standards
and products
– Used by employees to gain access to
corporate information
– Slashes the need for paper
Intranets and Extranets
 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): a
secure connection between two
points across the Internet
– Intranets and extranets often run over
VPN’s
Internet Issues
 Privacy
– Spyware: hidden files and information
trackers that install themselves secretly
when you visit some Internet sites
– Cookie: a text file that an Internet
company can place on the hard disk of a
computer system
Net Issues

Security
– Cryptography: converting a message into a
secret code and changing the encoded
message back to regular text
– Digital signature: encryption technique used
to verify the identity of a message sender for
processing online financial transactions
– Firewall: a device that sits between an
internal network and the Internet, limiting
access into and out of a network based on
access policies
Net Issues