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Sub topic : Repeaters

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Recap

In the previous class, you have learnt about

• Internet

• History of Internet

• Advantages of Internet

• Internet today

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On completion of this period, you would be

able to understand about

• Definition of a Repeater

• Importance of Repeaters

• Function of a Repeater

• Location of a Repeater

Objectives

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Definition of a repeater

• A Repeater is an electronic device that simply

regenerates a signal

• A connecting device between two segments of a

LAN

• It works at physical layer of OSI model

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Application layerPresentation layer

Session layerTransport layerNetwork layerData link layerPhysical layer Repeater

A

Physical layerData link layerNetwork layer

Transport layerSession layer

Presentation layerApplication layer

B

Repeater at physical layer

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• It can extend physical length of a LAN

• A repeater can overcome the 10Base5 Ethernet length restriction

• Repeater can divide the network in to segments

• Range of LAN can be increased

Importance of Repeaters

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• It receives a signal before it becomes too weak or

corrupted

• Regenerates the original bit pattern

• The repeater forwards the refreshed signal

• It works in the physical layer

Functions of Repeater

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• It has no filtering capability

• It is a regenerator, not an amplifier

• It does not perform any intelligent function

Functions of Repeater contd…

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Functions of Repeater contd…

Corrupted signal

Corrupted signal Regenerated signal

Left-to Right Transmission

Regenerated signal

Right- to- Left Transmission

Repeater

Repeater

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Location of a Repeater

• A repeater must be placed so that a signal reaches it

before any noise changes the meaning of any of its bits

• A repeater placed on the line before the legibility of the

signal becomes lost

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5

4

3

2

1

Repeater

Segment 1 Segment 2

1 1

5

4

3

2

1

Fig .3 Repeater connecting two segments of a LAN

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• It must be placed between two segments of same LAN

just before any noise changes the meaning of any of its bits

• Just before the signal collapses or change the meaning of bit

pattern

• A repeater placed on the line before the legibility of the signal

becomes lost can still read the signal well enough to determine

the intended voltages and replicate them in their original form

Capabilities of a Repeater

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• A repeater does not connects two LAN’s

• A repeater cannot connect two networks of different protocols

• A repeater does not act as an amplifier or as a filter

Limitations of a Repeater

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In this class, you have learnt about

• Importance of repeaters

• Definition of repeater

• Function of repeater

• Location of a repeater

Summary

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1. A Repeater is a device which connects ?

(a) Two LANs

(b) Two segments of a same LAN

(c) Two WANs

Quiz

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2. Repeater is a _____________

(a) Regenerator

(b) An Amplifier

(c) Filter

Quiz

17

1. Define Repeater

2. Explain the operation of a repeater

3. What are different functions of a repeater

4. What is the importance of a repeater

Frequently Asked Questions