This document discusses communication networks and the ISO OSI 7-layer model. It introduces key concepts in communication networks, including multiplexing, switching techniques like circuit switching and packet switching, and different network types like local area networks and wireless networks. It also covers network topologies, protocols, and the need for a layered approach exemplified by the seven layers of the ISO OSI model. The purpose is to describe the principles of communication networks and explain the OSI architecture.

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Chapter- 9: Communication Networks
Reference:
Garcia and Widjaja, “Communication
Networks”, McGraw Hill, 2006
Part - III
Principles of Electronic Communication

2. Department of Electronics and Communication Engineering, MIT, Manipal
Department of Electronics and Communication Engineering, MIT, Manipal
Module I
Introduction to Communication Networks
Objectives:
▪ To describe the principles of communication
networks
▪ List the different types of communication networks
▪ To explain the ISO OSI architecture

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Communication Networks
▪ Multiplexer
▪ Multiple access
▪ Source coding
▪ Error detection and correction
▪ Switching
▪ Signaling
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Introduction to Data Communication

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Department of Electronics and Communication Engineering, MIT, Manipal
Communication Networks
▪ Point-to-point communication
▪ Point-to-multipoint communication
▪ Broadcasting
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Introduction to Communication Networks

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Network switching
Three types of switching techniques are
▪ Circuit switching
▪ Message switching
▪ Packet switching
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Communication Networks
▪ Local Area Network(LAN)
▪ Wide Area Network(WAN)
▪ Metropolitan Area Network(MAN)
▪ Public Switched Network
▪ Wireless Network
▪ Satellite Network
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Types of communication networks

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Network topology
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Network protocols
Network protocols define rules and
conventions for communication between
network devices
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Need for layered approach
▪ Every layer will perform well-defined, specific
functions
▪ Modifications in one layer's functionality or
implementation does not affect the other layer
▪ A layer can be divided into sub-layers
▪ A layer can be eliminated or by-passed
▪ This multi-vendor approach benefits the end user
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Seven-layer architecture of ISO OSI
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Summary
In this module we have learnt:
▪ Key terms used in communication networks such as multiplexing,
multiple access, source coding, error detection and correction,
switching and signaling.
▪ Concept of point-to-point communication, point-to-multipoint
communication and broadcasting.
▪ Different types of network switching techniques such as circuit
switching, message switching and packet switching.
▪ Different forms of networks such as local area network, wide area
network, metropolitan network, public switch network, wireless
networks, satellite networks
▪ Network topology such as bus, star, ring, token ring, mesh and tree.
▪ Network protocols and need for layered approach.
▪ To draw the seven layer architecture of ISO OSI model and need for
each layer.
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Self Test
▪ List the different networks used for communication.
▪ Draw the various topology used in communication
networks.
▪ Define protocol and explain the need for network
protocols.
▪ For N devices in a network, what is the number of
cable links necessary for mesh, ring, bus and star
networks.
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Exercises
▪ Compare circuit switching and message switching
with packet switching.
▪ Give an advantage for each type of network
topology.
▪ What is LAN, WAN and MAN? Give one example for
each.
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