NETWORK DEVICESBy:

12BS(CS)02

Computer Science Department , QUEST

Data Communication

OUTLINES

o Network Devices.o Types Of Network Devices.

Network Device

Network Devices:o Any device capable of connecting to a network is considered

a network device. Some networking device are:o Repeatero Hubso Switcho Bridgeo Routero Gatewayo Modem

Repeater

o Network repeaters regenerate incoming electrical, wireless or optical signals. With physical media like Ethernet or WIFI, data transmissions can only span a limited distance before the quality of the signal degrades. Repeaters attempt to preserve signal integrity and extend the distance over which data can safely travel.

o A repeater is an object that increases a signal's strength, so it can be transmitted and received over a greater distance without a loss in quality.

o A radio repeater retransmits a radio signal.

Hub

o A central device that provide a common connection among the nodes.

o Hubs are work at the OSI Physical Layer.o Two types of hubs.

1) Active Hub:- Provide a path for digital signal as well as regenerate the signal.

2) Passive Hub:-Provide a path for electrical signal.

 Functioning of a Hub

o Receives a data packet.o Forwards it to all the remaining ports.

Switch

o A network switch (sometimes known as a switching hub) is a Computer network devices that is used to connect devices together on a  Computer network by performing a form of Packet switching. A switch is considered more advanced than a hub because a switch will only send a message to the device that needs or requests it.

What does it do?

o It establishes a temporary connection b/w the source and the destination and then terminates the connection when conversation is done

Modulator Demodulator (MODEM) 

o The word "modem" comes from "modulator- demodulator”

o Modulation: digital information to analog signal.

o Demodulation: analog signals back into useful digital information

Bridgeo Bridge are used to divide the network into segment.o It work in physical and data link layer.o As physical layer it regenerate the signal.o As data link layer it check the physical address or MAC address.o It can filter the traffic on the basis of MAC address.o It is used to interconnect the two LANs.o Three types of bridges

1) Transparent bridge.

2) Source routing bridge.

3) Translation bridge.

Types of Bridge

1) Transparent bridgeo Perform the function of blocking or forwarding on e basic of

MAC address. o Ethernet network are the example.

2) Source route bridgeo Use in Token ring network.o To make the specific decision about how the data is forward

to the network.

3) Translation bridgeo Used to convert one networking to another networkingo Like Token to Ethernet networking.

Router

o Router are the device that are connect two distinct network.

o Router are use the logical address such as IP address to make the decision.

o It operate the network layer in OSI model.o Routers have the ability to make intelligent

decisions as to the best path for delivery of data on the network.

Gateway

o Has the ability to connect dissimilar networks.o Any device that convert one data format t another.o It cannot change the data itself.o The conversion from one data format to another takes time,

and so the flow of data through a gateway is always slower than the flow of data without one.

THANK YOU