Transcript Managing Local Users and Groups

Introduction to
Computer Networks
Chapter 1
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Chapter Objectives
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Explain the need of networks
Explain history of computer networks (ARPANET)
Explain the types of computer networks
Explain Client/Server configuration
Explain layers of OSI model
Explain network selection criteria
Network Application
Explain Standards Organizations
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Computer Network
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Interconnection of two or more computers and
peripherals
Allows user to share and transfer information
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Need of Computer Networks
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Sharing Resources
Reduced Cost
Reduced time
Scalability
Reliability
Security
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History of Computer Networks
(ARPANET)
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ARPA designed for Department of Defense
(DOD), US
Small computers were connected to large
mainframe computers
IMPs were connected to each other through
modem
Supported different operating systems
Telenet and ftp services was provided by
ARPANET
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Types of Computer Networks
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Networks are classified depending on the
geographical area covered by the network
Computer
Networks
Local
Area Network
(LAN)
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Campus
Area Network
(CAN)
Metropolitan
Area Network
(MAN)
Wide
Area Network
(WAN)
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Local Area Network (LAN) - I
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Covers a small area
Connects computers and workstations covering a
local area like, office or home
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Local Area Network (LAN) - II
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Advantages of LAN:
 Improves productivity due to faster work
 Provides easy maintenance
 New systems can be installed and configured
easily
Disadvantages of LAN:
 Limited number of systems can only be connected
 Cannot cover large area
 Network performance degrades as number of
users exceeds
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Campus Area Network (CAN)
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Made up of multiple LANs within limited area
Connects different LANs in a campus
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Metropolitan Area Network
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Interconnects networks within a city
Supports data and voice transmission
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Wide Area Network
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Covers a wide geographical area which includes
multiple computers or LANs e.g. Internet
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Comparison of Networks
LAN
CAN
Connects computers
and workstations in
office or home.
Uses
IEEE
standard.
Low cost
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WAN
Connects two or more Interconnects
Connects
LANs within a
networks in a town or geographically
campus.
a city.
separated LANs.
Covers a local area of Covers privately
1 Km.
owned campus with
an area of 5 to 10
Kms.
Data Transmission
Rate – 10/100 Mbps
MAN
Covers larger area
Spans large
than LAN but smaller geographical area
area than WAN with more than 100 Kms.
an area of 2 to 100
Kms.
Data
Transmission Data
Transmission Data
Transmission
Rate – Variable
Rate - Variable
Rate – 64 Kbps or 2
Mbps
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High cost
Uses
IEEE
802 Uses ITU standard.
standard.
High cost (Repetitive) High cost (Repetitive)
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Case Study - I
MoneyMaker is a bank having its registered office at
Delhi. It has branches at Mumbai, Chennai,
Hyderabad and Bangalore. The operating departments
in the bank are Finance, Insurance, Loan, IT,
Marketing, Customer Service and HR. MoneyMaker
bank uses LAN as their computer network for each
department. All the branches of the bank from different
cities are connected through WAN. The bank is
expanding and decided to open its branches at
different locations in the city.
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Problem
Determine which type of network to be used within a
city
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Suggested Solution
Use LAN computer network for each department in the
new branch. MAN can be used for connecting the
different branches of the bank within the city
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Client/Server Configuration
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Consists of two elements, Client and Server
Server:
 A centralized element which provides resources to
client
 Manages data, printers or network traffic
Client:
 Manages local resources used by users such as
monitor, keyboard, CPU and peripherals
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OSI Model
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Run it through CBT
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Network Selection Criteria
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Helps to improve network functionality
Network
Criteria
Performance
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Reliability
Security
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Network Applications
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Financial Institution (Banking Sector)
Communication Services (Telecom Industry)
Internet Service (WWW, ISP)
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Standards Organizations
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Also known as Standards Development Organization
(SDO)
Develop, maintain, improve and revise standards
Classified as:
 ISO – Creates world wide industrial and commercial
standards
 ITU-T – Standardizes and regulates international radio
and telecommunication
 IEEE – Develops standards for power & energy, IT,
telecommunication, biomedical and healthcare
 ANSI – Creates standards for computer industry e.g.
FDDI
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Summary - I
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Computer network enables the user to share data
and network resources
Network allows remote users to communicate with
each other
Computer networks are divided into LAN, CAN,
MAN and WAN depending on the coverage area
LAN is a small network and easy to create
Client/Server configuration also called as two-tier
architecture, consist of two nodes, client and server
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Summary – II
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OSI model consists of seven layers and provides
standards for computer communication
Physical layer is responsible for actual transmission
of bits over the medium
Data Link layer is responsible for node to node
delivery of frames
Network layer is responsible for end to end delivery
of packets, and routing
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Summary - III
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Transport layer is responsible for end to end delivery
of the entire message
Session layer is responsible for establishing,
managing and terminating sessions
Presentation layer is responsible for translation,
encryption and data compression
Application layer is responsible for providing access
to the network
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Summary - IV
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Performance, reliability and security are the network
selection criterion which enables to choose efficient
network
Standards organizations like ISO and ANSI develop
technical and non- technical standards
International standards organizations are
International Standard Organization (ISO),
International Telecommunication Union (ITU),
Institute of Electrical and Electronics Engineers
(IEEE) and American National Standards Institute
(ANSI)
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