Introduction to Computer Networks

INTRODUCTION TO COMPUTER NETWORKS

Nidhi Jindalvs.hooda@ggnindia.dronacharya.info 1

Introduction to Computer Networks

A t t k iA computer network isa group of computersthat shares informationacross wireless or wiredacross wireless or wiredtechnology.

The computers can begeographically locatedanywhereanywhere.

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Introduction to Computer Networks

Resource SharingResource SharingHardware (computing resources, disks, printers)Software (application software)

f ShInformation SharingEasy accessibility from anywhere (files, databases)S h C bili (WWW)Search Capability (WWW)

CommunicationEmailEmailMessage broadcast

Remote computingDistributed processing (GRID Computing)

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Introduction to Computer Networks

Th t k t lThe network topologydefines the way inwhich computers,printers and otherprinters, and otherdevices are connected.

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Introduction to Computer Networks

Commonly referred to as a linear bus, all the devices on a bustopology are connected by one single cable.Uses a trunk orbackbone to which all of the computers on the networkconnect.

AdvantagesCheap and easy to implementRequire less cableDoes not use any specialized network equipment.

DisadvantagesNetwork disruption when computers are added or removedA break in the cable will prevent all systems from accessing the network.Difficult to troubleshoot.

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Introduction to Computer Networks

All computers/devices connect to a central device ll d h b i h E h d i i i lcalled hub or switch. Each device requires a single

cable .point-to-point connection between the device and hub.Hub is the single point of failureHub is the single point of failure

Advantages Easily expanded without disruption to the networkCable failure affects only a single useCable failure affects only a single useEasy to troubleshoot and isolate problems

DisadvantagesRequires more cableRequires more cableA central connecting device allows for a single point of failureMore difficult to implementp

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Introduction to Computer Networks

A tree topology combines characteristics of linear b d l ibus and star topologies.

Advantages Point-to-point wiring for individual segments.S d b l h d d fSupported by several hardware and software venders.

Disadvantages Overall length of each segment is limited by theOverall length of each segment is limited by the type of cabling used.If the backbone line breaks, the entire segment goes down.gMore difficult to configure and wire than other topologies.

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Introduction to Computer Networks

A frame travels around the ring,t i t h d If dstopping at each node. If a node

wants to transmit data, it adds thedata as well as the destinationaddress to the frame.address to the frame.The frame then continues aroundthe ring until it finds thedestination node, which takes thedest at o ode, c ta es t edata out of the frame.

Single ring – All the devices onthe network share a single cablegDual ring – The dual ringtopology allows data to be sentin both directions.

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Introduction to Computer Networks

Typically FDDI, SONET or Token Ring h l d ltechnology are used to implement a ring

network

dAdvantages Cable faults are easily located, making troubleshooting easier Ri k d lRing networks are moderately easy to install

Disadvantages

Expansion to the network can cause network disruptionA i l b k i th bl di t thA single break in the cable can disrupt the entire network.

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Introduction to Computer Networks

The mesh topology connects all devices (nodes) to each other for redundancy and fault toleranceeach other for redundancy and fault tolerance. It is used in WANs to interconnect LANs and formission critical networks like those used by banksand financial institutions.and financial institutions.

Disadvantage

Implementing the mesh topology is expensive andImplementing the mesh topology is expensive and difficult.

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Introduction to Computer Networks

Physical MediaInterconnecting DevicesComputersNetworking SoftwareApplications

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Introduction to Computer Networks

Networking media canbe defined simply asthe means by whichi l (d )signals (data) are sent

from one computer toanother (either bycable or wirelesscable or wirelessmeans).

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Introduction to Computer Networks

HUB, Switches, Routers,Wireless Access Points,Modems etc.

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Introduction to Computer Networks

In a client/servert k tnetwork arrangement,

network services arelocated in a dedicatedcomputer whose onlycomputer whose onlyfunction is to respondto the requests ofclients.

The server containsthe file, print,, p ,application, security,and other services in acentral computer thati ti lis continuouslyavailable to respond toclient requests. 14

Introduction to Computer Networks

Local Area NetworksLocal Area NetworksMetropolitan Area NetworksWide Area NetworksWireless NetworksHome NetworksInternetworks

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Introduction to Computer Networks

E ilE-mailSearchable Data (Web Sites)E-CommerceNews GroupsInternet Telephony (VoIP)Video ConferencinggChat GroupsInstant Messengers Internet Radiote et ad o

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Introduction to Computer Networks

Security in computer networksBandwidth improvement for datapcommunication over networksBetter Data rates

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Introduction to Computer Networks

Why star topology is most commonly usedtopology?List real life application of Hybrid networks.

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