Chapter6
TELECOMMUNICATIONS AND NETWORKS
Content
• The Networked Enterprise
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The Concept of a Network
Trends in Telecommunications
The Business Value of Telecommunications Networks
The Internet Revolution
The Role of Intranets
The Role of Extranets
• Telecommunications Network Alternatives
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A Telecommunications Network Component
Types of Telecommunications Networks
Telecommunications Media
Telecommunications Processors
Network Topologies
Network Architectures and Protocols
The Concept of a Network
• What is network? Network means an
interconnected or interrelated chain, group, or
system.
• The concept of networks can be expressed as a
mathematical formula that calculates the number
of possible connections or interactions in a oneway communication environment:
N (N -1), or N2 - N . N refers to the number of nodes
(points of connection) on the network.
Trends in Telecommunications
The Business Value of
Telecommunications Networks
The Internet Revolution
• The revolution of internet:
– December 1991: It had about 10 servers.
– January 2004: The Internet was estimated to have more than 46 million
connected servers with a sustained growth rate in excess of 1 million servers
per month.
– January 2007: The Internet was estimated to have more than 1 billion users
with Web sites in 34 languages.
– The Internet is constantly expanding as more and more businesses and other
organizations and their users, computers, and networks join its global Web.
– To connected to internet for access we need ISP.
– After you connected to internet we need to used Internet application to
request the internet service.
– Business use of the Internet has expanded from an electronic information
exchange to a broad platform for strategic business applications.
– The Business Value of the Internet is cost saving.
Popular uses of the Internet
how a company can use the Internet for business
How companies are deriving business value from their e-business and e-commerce applications
The Role of Intranets
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What is Intranet? An intranet is a network inside an
organization that uses Internet technologies for
information sharing, communications, collaboration,
and the support of business processes.
The business value of intranet is:
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Communications and Collaboration: Intranets can
significantly improve communications and
collaboration within an enterprise.
Web Publishing: The advantage of developing and
publishing hyperlinked multimedia documents to
hypermedia databases accessible on World Wide Web
servers has moved to corporate intranets.
Business Operations and Management: Intranets are
also being used as the platform for developing and
deploying critical business applications to support
business operations and managerial decision making
across the inter-networked enterprise.
Intranet Portal Management: Organizations must
employ IT and IS professionals to manage the functions
of the intranet along with maintaining the various
hardware and software components necessary for
successful operations.
The Role of Extranets
• What is extranet?
extranets are
network links that
use Internet
technologies to
interconnect the
intranet of a
business with the
intranets of its
customers,
suppliers, or other
business partners.
A Telecommunications Network
Component
• Terminals: input/output device that uses telecommunications networks to
transmit or receive data(Ex: Personal computers, network computers, net
boxes, or information appliances)
• Telecommunications processors: which support data transmission and
reception between terminals and computers(modems, switches, and
routers).
• Telecommunications channels: over which data are transmitted and
received(Wire and wireless).
• Computers: all sizes and types are interconnected by telecommunications
networks so that they can carry out their information processing
assignments. (mainframe or microcomputer).
• Telecommunications control software: consists of programs that control
telecommunications activities and manage the functions of
telecommunications networks(telecommunications monitors, network
operating, Web browsers).
The five basic components in a
telecommunications network
Types of Telecommunications
Networks
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Wide Area Networks: Telecommunications networks covering a large geographic
area.
Metropolitan Area Network: Networks that cover a large city.
Local Area Networks: connect computers and other information processing
devices within a limited physical area, such as an office, classroom, building,
manufacturing plant, or other worksite.
Virtual Private Networks: A virtual private network is a secure network that uses
the Internet as its main backbone network but relies on network firewalls,
encryption, and other security features of its Internet and intranet connections and
those of participating organizations.
Client/Server Networks: They are interconnected by local area networks and share
application processing with network servers, which also manage the networks.
Network Computing: It views networks as the central computing resource of any
computing environment.
Peer-to-Peer Networks: The use for peer-to-peer networks is the downloading and
trading of files and PeerCast.
Type of Telecommunication Network
LAN
WAN
VPN
Network Computing
Cient/Server
Peer-to-Peer Networks
Telecommunications Media
• Wired Technologies:
– Twisted-Pair Wire
– Coaxial Cable
– Fiber Optics
• Wireless Technologies:
– Terrestrial Microwave: involves earthbound microwave systems that
transmit high speed radio signals in a line-of-sight path between relay
stations spaced approximately 30 miles apart.
– Communications Satellites: high-earth orbit (HEO) communications
satellites are placed in stationary geosynchronous orbits
approximately 22,000 miles above the equator.
– Cellular and PCS Systems
– Wireless LANs
– Bluetooth
– The Wireless Web
Wired Technology
Wireless Application Protocol(WAP)
Telecommunications Processors
• Modems: They convert the digital signals from a
computer or transmission terminal at one end of a
communications link into analog frequencies that can
be transmitted over ordinary telephone lines.
• Inter-Network Processors: Telecommunications
networks are interconnected by special-purpose
communications processors such as switches, routers,
hubs, and gateways.
• Multiplexers: is a communications processor that
allows a single communications channel to carry
simultaneous data transmissions from many
terminals(FDM and TDM).
Comparing modem and telecommunications
technologies for Internet and other network access
Examples of some of the
communications processors
Network Topologies
• Bus: It is a network in which local processors
share the same bus, or communications
channel.
• Ring network ties local computer processors
together in a ring on a more equal basis.
• Star network ties end-user computers to a
central computer.
The ring, star, and bus network
topologies
Network Architectures and Protocols
• Protocols: a standard set of rules and procedures
for the control of communications in a network.
• Network Architectures:
– The OSI Model
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Layer 1: The physical layer
Layer 2: The data link layer
Layer 3: The network layer
Layer 4: The transport layer
Layer 5: The session layer
Layer 6: The presentation layer
Layer 7: The application layer
– The Internet’s TCP/IP
OSI and TCP/IP Model