This document provides an introduction to computer networks. It defines data communication as the exchange of data between two devices via transmission medium. It presents a simplified data communication model including the message, sender, medium, receiver, and protocol. It explains that point-to-point communication is not practical for distant or large sets of devices, so a communications network is used instead. Networks allow for better connectivity, communication, sharing of resources, and overcome geographic limits to access remote data with the goal of universal communication between any devices. Networks can also be classified based on transmission media, size, management method, and topology.

1. An Introduction to Computer
Networks
Amitava Nag
Assistant Professor
Dept. of IT, AOT

2. 1. What is communication?
2. What is data communication?
Ans: Data communication is the exchange of
data between two devices via some form of
transmission medium.

3. Data Communication Model
Network
Source Destination
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4. Simplified Communication Model
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5. Simplified Data Communications
Model
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6. Components
• Message
– Information (data to be transmitted
• Sender
– That sends the data
• Medium
– Physical path that carries data
• Receiver
– Receives data in form of signal
• Protocol
– A set of rules that governs data communications.
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7. Networking
• Point to point communication not usually
practical
– Devices are too far apart.
– Large set of devices would need impractical
number of connections.
• Solution is a communications network.
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8. Simplified Network Model
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9. Computer Network
A communication system for connecting computers
/hosts and share resources

10. Why Networking?
• Sharing information — i.e. data
communication
• Do you prefer these?
• Or this?
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11. Why Networking?
Why?
 Better connectivity
 Better communication
 Better sharing of resources
 Bring people together
 Overcome geographic limits
 Access remote data
Goal: Universal Communication (any to any)

12. How many kinds of Networks?
• Depending on one’s perspective, we can classify
networks in different ways
• Based on transmission media: Wired (UTP, coaxial cables, fiber-optic
cables) and Wireless
• Based on network size: LAN and WAN (and MAN)
• Based on management method: Peer-to-peer and Client/Server
• Based on topology (connectivity): Bus, Star, Ring …
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