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1. Introduction to
Computer Networks

2. Computer Network
 Interconnection of two or more computers and
peripherals
 Allows user to share and transfer information

3. Need of Computer Networks
• Sharing Resources
• Reduced Cost
• Reduced time
• Scalability
• Reliability
• Security

4. History of Computer Networks (ARPANET)
• 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

5. Types of Computer Networks
 Networks are classified depending on the
geographical area covered by the network

6. Local Area Network
 Covers a small area
 Connects computers and workstations covering a
local area like, office or home

7. Local Area Network
• 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

8. Types of LAN
 LANs are classified depending on the techniques
used for data sharing

9. Campus Area Network (CAN)
 Made up of multiple LANs within limited area
 Connects different LANs in a campus

10. Metropolitan Area Network
• Interconnects networks within a city
• Supports data and voice transmission

11. Wide Area Network
• Covers a wide geographical area which includes multiple
computers or LANs e.g. Internet