CSC461-CN-Lecture-1-Jan-9-2013

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BITS PilaniPilani | Dubai | Goa | Hyderabad

Computer NetworksLecture-1

Rahul Banerjee, PhD (CSE)

Professor, Department of Computer Science & Information Systems

E-mail: [email protected]


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BITS Pilani, Deemed to be University under Section 3 of UGC Act, 1956

About the focus of the course

How shall this course be conducted?

Resources & Timelines for the course

What is a Computer Network and why do weneed it?

Basic types of Computer Networks andInternetworks

Select References to the literature

Summary

Interaction Points


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AbouttheFocusoftheCourse

This course aims at:

Learning about the basics of ComputerNetworking

Developing an ability to:Conceptualize a simple network,Design an elementary network,Simulate and build a multi-protocol network,Configure a simple network,Analyze a give network design &Diagnose issues / problems associated with a simple

state-of-the-art Network / Internetwork


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TheCoursePlanMethodologytobeused:

42Classroomlectures(threeperweek,aspertheprovidedcoursehandout)

LearningReinforcementsthrough:OnlineDiscussionForum(attheNalandalearningmanagementsystem:hp://nalanda.bits-pilani.ac.in/)

Case-studiesinterlacedwithdesigndiscussions(inclassroom)Mini-project/InvesQgaQveProject/LaboratoryExperiments:25% Self-studyassignments

OnlyONETest:Mid-SemesterTest30%uizzes5% ComprehensiveExaminaQon30%

(c) Dr. Rahul Banerjee, BITS Pilani, INDIA


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ResourcesfortheCourse Course Home Page:

URL: http://universe.bits-pilani.ac.in/pilani/rahulbanerjee/ComputerNetworks This page shall have the original slides developed by me for a

group of lectures on related topics .

Course Forum at the Nalanda open-learningportal: URL: http://nalanda.bits-pilani.ac.in This page shall carry links to:

Discussion Forum Reading advisories Challenges for bright students Occasional Links to News items of contemporary relevance to the topic

under discussion Laboratory tips developed with the help of student volunteers Indicative Solutions to Test / Quiz / Compre. Exam papers

IntraBITS Page for Course: http://intraBITS.bits-pilani.ac.in


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AddiQonalResourcesfortheCourse

Digital Library resources:As accessible from the http://library.bits-pilani.ac.in >

Access to select complete E-books via Books 24x7 Laboratory resources:

Fixed and Mobile Networking equipment located at IBM Laboratory for Open Source Computing, Microsoft Laboratory for Mobile Computing and

Chamber Consultation Hours: Tuesday: 1700 1800 Hrs.


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WhatisaComputerNetwork?

A Computer Networkis an interconnectedgroup ofautonomous computing nodes whichcan meaningfullyand (preferably) controllablycommunicate with one-another. Such communication requires presence ofone or more sets of rules and

conventions which are encoded as commands and their correspondingresponses.

Such rules and conventions that allow meaningful and unambiguouscommunication between members of a Computer Networkare collectivelycalled Network Protocols.

In real-life networks, often a set of relatedfunctions are handled by a group of closelytied protocols which constitute a ProtocolFamily(also known as a Protocol Suite).


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DefiningaComputerNetwork

Defining a Computer NetworkA Computer Network is an interconnected group of

autonomous computing nodes which: Use a well-defined, mutually-agreed set of rules and conventions

known as Protocols,

Interact with one-another, if duly authenticated and authorized,meaningfully;

Allow resource-sharing preferably in a predictable andcontrollable manner.

Autonomous computing nodeA computer / node that has its own processing capabilities and

that does not act under the control of any other computer / isknown as an Autonomous Computer or an AutonomousComputing Node.

It should NOT be confused with the traditional Dumb Terminalsin centralized computing environments.


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ElementsinvolvedinaNetwork/Internetwork

NodesRegular computing

nodes

Network extension /interconnection devices

Network InterfacesNICs / On-board ChipsWireless interfacesWireline interfaces

LinksWireline linksWireless links

Strategies, Algorithms & Protocols: H/W, S/W, F/W level implementationsWednesday, 9 January 13 9(c)Dr.RahulBanerjee,BITS-Pilani,INDIA

Nodes:whereprocessingandcommunicaQoncapabiliQesco-exist

Hosts:end/intermediatenodeswherealllevels/layersincludingthosebelongingtoapplicaQonsexist



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(c)Dr.RahulBanerjee,BITSPilani,INDIA 10

ApplicaQonsofComputerNetworks

NumerousapplicaQonsofcomputernetworkingarepossible.

Someofthemostpopularonesinclude:ElectronicMailWeb-browsingDigitalLibrariesVideo-on-DemandFileTransferVideo/AudioConferencing/ImmersiveTelepresenceSocialNetworkingWeb-ServicesE-Commerce&MobileCommerce

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TypesofComputerNetworks(1of2)

Spread,size,inter-node-distanceandpurposebasedclassificaQon:PersonalAreaNetworks(PANs):Oen,Wireless:WirelessPersonalAreaNetworks(WPANs)

LocalAreaNetworks(LANs):WirelineLANs(LANs)&WirelessLANs(WLANs)

MetropolitanAreaNetworks(MANs):WirelineandWirelessMANsWideAreaNetworks(WANs):Wireline/Wireless,Fixed/Mobile,Planet-wide/Interplanetary

SensorNetworks(SNs)&WirelessSensorNetworks(WSNs)StorageAreaNetworks/SystemAreaNetworks(SANs)BodyAreaNetworks(BANs)CarAreaNetworks(CANs)


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TypesofComputerNetworks(2of2)

VirtualizaQon-basedclassificaQon:VirtualLocalAreaNetworks(VLANs)VirtualPrivateNetworks(VPNs)OverlayNetworks

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ConvenQonalClassificaQonofComputerNetworks

Class One: Function-based classification Data Networks Voice Networks Multimedia Networks

Class Two: Location-and-Distance-basedclassification

Personal Area Networks(PANs)

Local Area Networks(LANs)

Metropolitan AreaNetworks (MANs)

Wide Area Networks(WANs) .

ClassThree:Forwarding-basedclassificaQon

SwitchedNetworks Circuit-SwitchedNetworks Packet-SwitchedNetworks

SharedNetworksHybridNetworks

ClassFour:Ownership-basedclassificaQonPublicNetworks

PrivateNetworksVirtualPrivateNetworks

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LocalAreaNetworks(LANs)

The term LAN stands for Local Area Network. The term local area in the world of networking

usually refers to:

a geographically contiguous area in which the inter-node distance is lesser than or equal to one

kilometer.

LANs are always owned by a single entity (anorganization or individual)

Examples of popular LAN technologies include theEthernet in wired (wireline) category and Wi-Fi in the

wireless category

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(c)Dr.RahulBanerjee,BITSPilani,INDIA

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LocalAreaNetworks...

A LAN is local in the sense that it is installed in alocal location like a local office, a laboratory, abuilding or a campus.

Although, normally, in a LAN, the inter-nodedistance does not exceed a kilometer; in most ofthe real-life situations, it is far less than thisceiling.

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InterconnecQonofnodes/interfaces/networks

Media-based interconnection perspective Guided / Unguided Noisy / Noiseless Broadcast / Non-broadcast

Link-based interconnection perspective Secure / Insecure Logical / Physical Point-to-Point / Multi-point

Physical Links: those entities that provide physical path (directpaths between neighbouring nodes (point-to-point / point-to-

multi-point) for data delivery over guided or unguided media Logical Links: an abstraction showing the logical path of data

delivery at layers higher than the physical layer


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PersonalAreaNetworks(PANs)

The term PAN stands for Personal AreaNetwork.

Typically these networks are small in size,belong to a single person and are limited tohis / her environment within a small area likehis room, body or garden etc.

PANS mostly use short-range wirelesstechnologies for interconnecting various nodesthat comprise them.

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LocalAreaInternetwork/Intranet

Traditionally, a Campus Internetwork is a campus-wideinternetwork of individual LANs which may be geographically

spread over the part or whole of a single campus. This sometimes

called campus intranet.

In common practice, the entire campus internetwork including itscommunication subnet is wholly owned by a single organizationor institution.

Usually, the campus internetworks use LAN technology; however,it is possible to use WAN technology, when so desirable.

The latter may be desirable in some cases when the campus isvery large and comprises of a vast set of buildings spread over it.

Protocols used in both of these cases at the lower layers, are,

generally, different.

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MetropolitanAreaNetworks(MANs)

The term MAN stands for Metropolitan AreaNetwork.

A computer network that is not usually ownedby a single organization / entity and that isspread over a metropolitan city area is calleda Metropolitan Area Network.

Normally, in a MAN, the inter-node distancedoes not exceed ten kilometers. This,however, is not a hard-and-fast rule.

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WideAreaNetworks(WANs)

The term WAN stands for Wide Area Network. A computer network that is not usually owned by a

single organization / entity and that is spread over an

area larger than that of any city of operation is called aWide Area Network .

A WAN may be spread over several cities / towns, astate, a country or even a continent.

In many a cases, when people say WAN, they actuallymean Wide Area Internetwork (WAI), however!

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ComparingComputerNetworkswith

DistributedSystems

Terms Computer Network and Distributed Systemmust NOT be used interchangeably since:

In the former, locations and elements ofnetwork remain visible to the user;

In the latter, the underlying network remainstransparent to the user who sees the systemas a uni-processor.

Similar differences can be cited in case of NetworkOperating Systems and Distributed Operating Systems.

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Summary Intranet: Completely private network of networks

Wireline Wireless

FixedMobile

Hybrid The Internet: Global public network of networks Wireline Wireless

FixedMobile

Hybrid Extranet: Intranets interconnected via the Internet

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Concluding remarksNetworkingsupportofsomekindisalreadyinsidemostoftheoperaQngsystemsweusetodayinvarietyofformsonNotebooks,Laptops,WorkstaQonsandServers.AllSmart-phonesandseveralset-topboxessupportittoo.

Subsequentlecturesshallintroduceyoutothefollowingtopics:

Internetworks NetworkArchitectures Performance ualityofService Reliability Security



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References

Larry L. Peterson & Bruce S. Davie: Computer Networks: A Systems Approach,Fifth Edition, Morgan Kaufmann / Elsevier, New Delhi, 2011.

S. Keshav: Computer Networking: An Engineering Approach, PearsonEducation, New Delhi, 1997.

A. S. Tanenbaum: Computer Networks, Fifth Edition, Pearson Education, NewDelhi, 2012.

Y. Zheng and S. Akhtar: Networks for Computer Scientists and Engineers,Oxford University Press, New York, 2002.

A. Leon Garcia and I. Widjaja: Communication Networks: FundamentalConcepts and Key Architectures, Second Edition, Tata McGraw-Hill, New Delhi,2004.

Mohammed G. Gouda: Elements of Network Protocol Design, Wiley StudentEdition, John Wiley & Sons (Pte.) Ltd., Singapore, 2004.

Thomas G. Robertazzi: Computer Networks and Systems: Queuing Theory andPerformance Evaluation, Third Edition, Springer-Verlag, New York, 2000.

Dr. Rahul Banerjee, BITS, Pilani (India)09/01/13 (c)Dr.RahulBanerjee,BITSPilani,INDIA 24


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AnExampleofaComputerNetwork


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WhatisanInternetwork?

09/01/13 (c)Dr.RahulBanerjee,SDETUnit,BITS-Pilani,INDIA 2609/01/13 (c)Dr.RahulBanerjee,BITSPilani,INDIA 26


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Project BITS-Connect 2.0

The Immersive Tele-presence Rooms

This is how an18-seater

immersive tele-

presence room

looks like at all

the Indiancampuses.

Chancellorsofficeisequippedwith

onetwo-seatersystem


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Project BITS-Connect 2.0


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BITS PilaniPilani | Dubai | Goa | Hyderabad

Rahul Banerjee

Thank you for your kind attention!

CSC461-CN-Lecture-1-Jan-9-2013

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Transcript of CSC461-CN-Lecture-1-Jan-9-2013