A network consists of two or more connected computers that share resources. There are three main types of networks: local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). LANs are confined to a small area like a building or office. MANs cover larger areas like cities. WANs connect even larger geographic areas spanning hundreds or thousands of kilometers.

1. Introduction to Network
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2. Objectives
• Explain what is network.
• Explain and differentiate different types of LAN.
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3. Introduction
A network consists of two or more computers connected to
each other in order to share resources.
Networks have become a major tool for many
organizations to meet data processing and data
communication needs.
Security services that protect the data, processing and
communication facilities, must also be distributed
throughout the Networks.
Network security should be an integral part of the whole
network and should be important to all users.
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4. Types of Networks
Depending on geographical extents, networks may be
classified as:
• Local Area Network (LAN)
• Metropolitan Area Network (MAN)
• Wide Area Network (WAN)
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5. Types of Networks contd..
Local Area Network (LAN)
A LAN is confined to a relatively small area. It is generally
limited to a geographic area such as a school, building or an
office. Typical radius of a LAN is a few hundreds of meters.
In a typical LAN configuration, one or more computers are
designated as the file server. Computers connected to the file
server are called workstations.
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6. Types of Networks contd..
Metropolitan Area Network (MAN)
A Metropolitan Area Network (MAN) covers larger
geographical areas than LAN, such as cities.
By interconnecting smaller networks within a large
geographic area, information is easily disseminated
throughout the network.
Large organization and government agencies often use a
MAN to establish their communication.
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7. Metropolitan Area Network (MAN) contd..
Physical security of communication medium is not within the
control of the organization.
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8. Types of Networks contd..
Wide Area Network (WAN)
Wide Area Networks (WANs) connect larger geographic
areas covering hundreds and even thousands of kilometers,
such as the whole of India or around the globe.
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