Telecommunications

and Networks
Learning Objectives
 Understand the concept of a network
 Identify major developments and trends in the industries,
technologies, and business applications of telecommunications
and Internet technologies
 Provide examples of the business value of Internet, intranet, and
extranet applications
 Identify the basic components, functions, and types of
telecommunications networks used in business
 Explain the functions of major components of
telecommunications network hardware, software, media, and
services
 Identify the various transmission media

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Telecommunication Trends

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 Telecommunications-Based
Services

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Internet Networking Technologies
 Internet networking technologies are being
used as technology platform
 Web browser suites
 HTML Web page editors
 Network management software
 Firewalls
 Being applied in Internet, intranet, and
extranet applications
 Reinforces previous move toward client/server
networks based on open-systems architecture

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Wireless Technologies
 Radio Frequency
 Bluetooth
 Infra Red
 Satellite Transmission

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Value of Telecommunications
Networks

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The Internet Revolution
 The Internet has become a global information
superhighway
 Millions of smaller, private networks operating
independent of, or in harmony with, each
other
 10 servers in 1991 to over 46 million today
 Sustained growth in excess of 1 million
servers per month
 No central computer system
 No governing body
 Based on common standards
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Internet Applications
 Most popular Internet applications and uses
 E-mail
 Instant messaging
 Browsing the Web
 Newsgroups
 Chat rooms
 Publish opinions, subject matter, creative work
 Buy and sell
 Downloading (data, software, reports, pictures,
music, videos)

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Business Use of the Internet

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Business Value of the Internet

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The Role of Intranets
 Many companies have sophisticated and
widespread intranets, offering…
 Detailed data retrieval
 Collaboration
 Personalized customer profiles
 Links to the Internet
 Intranets use Internet technologies
 Web browsers and servers
 TCP/IP network protocols
 HTML publishing and databases

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Intranets
 Intranets are protected by…
 Passwords
 Encryption
 Firewalls
 Customers, suppliers, and other business
partners can access an intranet via extranet
links

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Business Value of Intranets
 Intranets support
 Communications and collaboration
 Business operations and management
 Web publishing
 Intranet portal management

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Intranets as Information Portals

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Extranets
 Network links that use Internet technologies to
connect the intranet of a business to the
intranets of another
 Virtual Private Networks
 Direct private network links, or private secure
Internet links between companies
 Unsecured Extranet
 Link between a company and others via the
Internet, relying on encryption of sensitive
data and firewall security systems

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Extranet Connectivity

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Business Value of Extranets
 Web browser technology makes customer and
supplier access to intranets easier and faster
 Another way to build and strengthen strategic
relationships
 Enables and improves collaboration between a
business, customers, and partners
 Facilitates online, interactive product development
and marketing

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Telecommunications Network Model
 A telecommunications network is any
arrangement where
 A sender transmits a message
 To a receiver
 Over a channel
 Consisting of some sort of medium

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Telecommunications Network
Components
 Terminals
 Any input/output device that uses networks
to transmit or receive data
 Telecommunications processors
 Devices that support data transmission,
reception
 Telecommunications channels
 Media over which data are transmitted,
received
 Computers
 All sizes and types
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Types of Communications
Networks
 Primary types of communications networks
 Wide Area
 Local Area
 Virtual Private
 Client/Server
 Peer-to-peer

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Wide Area Network (WAN)
 Telecommunication network that covers a large
geographic area

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Local Area Network (LAN)
 Connects
computers
within a limited
physical area,
such as an
office,
classroom, or
building

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Virtual Private Networks (VPN)
 Used to establish secure intranets and extranets
 The Internet is the main backbone network
 Relies on network firewalls, encryption, and
other security features to build a “pipe”
through the Internet
 Creates a private network without the high
cost of a separate proprietary connection

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Virtual Private Network

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Client/Server Networks
 Clients
 End user personal computers or networked
computers
 Servers
 Used to manage the networks
 Processing
 Shared between the clients and servers
 Sometimes called a two-tier architecture
 Larger computer systems are being replaced with
multiple client/server networks

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Client/Server Network

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Peer-to-Peer Networks
 Central Server Architecture
 P2P file-sharing software connects all PCs
to a central server
 When a PC requests a file, the server
searches
all active peers on the network
 The server sends the requesting PC a list of
links to all active peers who have the file
 Clicking a link connects the two PCs and
automatically transfers the file to the
requesting PC
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Telecommunications Media
 Twisted-Pair Wire
 Ordinary telephone wire
 Copper wire is twisted
into pairs
 Coaxial Cable
 Sturdy copper or
aluminum wire wrapped
with spacers to insulate
and protect it
 Fiber-Optic Cable
 One or more hair-thin
filaments of glass
fiber wrapped in a
protective jacket
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Wireless Technologies
 Terrestrial Microwave
 Earthbound microwave systems transmit
high-speed radio signals
 Follows a line-of-sight path between relay systems
spaced about 30 miles apart
 Communications Satellites
 Serve as relay stations
 Use microwave radio signals
 Earth stations beam signals to the satellites
 Not suitable for interactive, real-time processing

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Wireless Technologies
 Cellular and PCS Telephone and Pager Systems
 Geographic areas are divided into cells
 Each cell has a low-power transmitter or radio relay
antenna
 Computers and other communications processors
coordinate and control the transmissions to and from
mobile users
 Wireless LANS
 Uses wireless radio-wave technology to
connect PCs within an office or a building
 Can be high-frequency, similar to digital
cellular, or low frequency (spread spectrum)

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Wireless Technologies
 Bluetooth
 Short-range wireless technology
 Connects PCs to devices, such as a printer
 Fairly low cost to implement
 Other Wireless Systems
 Cellular phones
 Mobile radio
 PDAs
 Telecommunications networks now play vital and
pervasive roles in
 Web-enabled e-business processes
 Electronic commerce
 Enterprise collaboration
 Other applications that support business operations,
management, and strategic objectives
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Telecommunications Processors
 Modems
 The most common type of communications
processor
 Converts a digital signal to an analog
frequency that can be transmitted over phone
lines, then back into a digital signal
 Modulation and demodulation

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Inter-Network Processors
 Switch… makes connections between
telecommunications circuits in a network
 Router… intelligent communications processor
that interconnects networks based on different
protocols
 Hub… a port-switching communications
processor
 Gateway… connects networks with different
communications architectures

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Communications Processors

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Communications Processors
 Multiplexer… allows a single communications
channel to carry simultaneous data
transmissions from many terminals
 In time division multiplexing (TDM), the
multiplexer divides the time each terminal can
use the high-speed into short time slots
 Multiplexers increase the number of
transmissions possible
 Does not increase the number of physical
data channels

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Network Topologies
 Topology - The structure of a network
 Star Network - Ties end user computers to a central
computer
 Ring Network - Ties local computer processors together
in a ring on a relatively equal basis
 Bus Network - Local processors share the same
communications channel
 Mesh Network - Uses direct communications lines to
connect some or all of the computers in the ring to
each other

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Network Topologies

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OSI and TCP/IP Models
 Open Systems Interconnection (OSI) Model
 A seven-layer model that serves as a
standard model for network architectures
 Model for how messages should be
transmitted between two points in a network
 Each layer adds functions
 Transmission Control Protocol/Internet Protocol
(TCP/IP)
 A five-layer telecommunications protocol used
by the Internet

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OSI and TCP/IP Models

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