CSC461-CN-Lectures-9-10-Feb.-1-2013

7/28/2019 CSC461-CN-Lectures-9-10-Feb.-1-2013

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BITS PilaniPilani | Dubai | Goa | Hyderabad

Network Topologies, Performance

and VirtualizationLectures - 9 &10, February 1, 2013Rahul 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

Network Topologies Network Virtualization Network-based Virtualization Current State-of-the-art and Evolving Research

Directions From Clusters and Grids to Clouds Wearable Computing Ubiquitous or Pervasive Computing

Select References to the literature Summary

Interaction Points


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3

ABusTopologybasedComputer

Network

SHAREDBUS

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

N1 N2 N3 N4


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Robert Metcafes Ethernet The original Ethernet protocol proposed and

implemented by Robert Metcafe was actually basedon 1-p CSMA/CD protocol

It did have a scheme that allowed greedy access tothe channel by a station which led to lower efficiency

Schemes like Random Back-off / Exponential Back-off were devised to improve the efficiency to a certainextent

01/02/13 (c) Dr. Rahul Banerjee, SDET Unit,BITS-Pilani, INDIA

4


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AnEthernetLAN

5 (c) Dr. Rahul Banerjee,BITS, Pilani, India

PersonalComputer

WorkstaFon

WorkstaFonWorkstation


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ABusTopology-basedNetwork


TheEthernetSwitch

PersonalComputer

NetworkPrinter

WorkstaFon

WorkstaFon

LaptopComputer

WorkstaFon

TabletPC


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ASamplerameormat

n-BytePreambleStart-of-rameDelimiterDesFnaFonAdd.SourceAddress

Dataield

Padield

LengthofData

Checksum



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AStarTopologybasedNetwork

C

C

C

Switch


S

N1

N2

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Fixed

LasersElectronic

Switches

GxG

MEMS

Group 1

LxM

Crossbar

Linecard 1

Linecard 2

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Linecard 1

Linecard 2

LinecardL

LxM

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Linecard 1

Linecard 2

LinecardL

Group G

MxL

Crossbar

Linecard 1

Linecard 2

LinecardL

Electronic

SwitchesOptical

Receivers

Group 1

MxL

Crossbar

Linecard1

Linecard2

LinecardL

Group 2

MxL

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Linecard1

Linecard 2

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Group G

GxG

MEMS

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GxG

MEMS

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Static

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Switch:TheBasisoftheStarTopology

Dr. Nick McKeown, Stanford University


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ATreeTopologybasedNetwork

NC1 NC2

NC11

NR

NC21

NC22

NC12



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ARingTopologybasedNetwork

C

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ARingTopologybasedNetwork

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(c) Dr. Rahul Banerjee, BITS, Pilani, India 13

SummaryofNetworkTopologies

Bus Topology Tree Topology Ring Topology

Single Double

Star Topology Irregular Topology Complete Topology


14/48BITS Pilani, Deemed to be University under Section 3 of UGC Act, 1956

LAN Virtualization: LAN Emulation Virtual LANs (VLANs)

WAN Virtualization: WAN Emulation Virtual Private Networks (VPNs)

OvertheInternetOverNon-InternetInfrastructureSub-IP-levelVPNs IP-levelandHigherLevelVPNs

Network Virtualization



Current State-of-the-art and Evolving ResearchDirections

From Clusters and Grids to Clouds Wearable Computing Ubiquitous or Pervasive Computing

Select References to the literature Summary

Interaction Points



Network-based Virtualization


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OfClusters,GridsandClouds Networks:

Asetofautonomouscompute/communicaFonnodesinterconnectedforthepurposeofmeaningfulresourcesharing,requiresupporFngprotocolstacks,not

transparenttotheusers

Clusters Homogeneous(plaorm/OS),allinvolvednodesoYenbelongtoasingleenFty

andfrequentlydesignedforhigh-performancecompuFng,maybelimitedtooneormorerackswithinthesameroom(example:HPCclusters),easiesttodeploy

andmanage

Grids OYenheterogeneous(plaorm/OS),requentlyspreadovermulFplenetworks

andnetworktypes,mayinvolvesingleormulFpleorganizaFons,requiregreater

effortindeploymentandadministraFon

Clouds Maybepublic,privateandhybrid,supportmulFplelevelsofabstracFons/

virtualizaFon,typicallyspreadoverwideareas,expectedtobetransparenttothe

user,offerthehighestlevelsofredundancy/availability,

F

ebru

ary

1,

2013

(c

)Dr

.Ra

hu

lBaner

jee

,BITSPilan

i,

INDIA


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Afewpointsofsignificance

VirtualizaFonistheunderlyingcommontechnologyinvolvedinallthethreeparadigms

Networkingisthekeyenableringredientineachofthesecases

Cost-effecFveness,robustnessandscalabilityimproveaswemovefromclustertocloudbut

overheadsandinternalcomplexityaddup

F

ebru

ary

1,

2013

(c

)D

r.

Ra

hu

lBaner

jee

,BITSPilan

i,

INDIA

f Cl d & i d


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TypesofClouds&Associated

VirtualizaFon

TypesofClouds:ClassificaFon-1 PublicClouds(mulF-tenancy,widevariaFons,mulF-

service,on-demandcapacityaddiFonacommonfeature)

PrivateClouds(singletenancy,limitedvariaFons,highercapitalinvestments,greatercontrol,moresecure)

HybridClouds(near-opFmalbestofbothworlds,ifconfiguredwell)

TypesofClouds:ClassificaFon-2 InfrastructureCloud,ComputaFonalCloudetc.

TypesofClouds:ClassificaFon-3 Plaormasaservice,SoYwareasaservice,Storageasa

service,CollaboraFon&SharingServicesetc.

F

ebru

ary

1,

2013

(c

)D

r.

Ra

hu

lBaner

jee

,BITSPilan

i,

INDIA


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Case-StudyofofaNetwork-BasedMulF-siteCollaboraFonSystemDesign



Project BITS-Connect 2.0


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WearableCompuFngElements

ebruary1,2013 (c)Dr.RahulBanerjee,BITSPilani,INDIA


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E-abricofaWearableGarment



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Paradiso&StarnersShoesfor

ElectricalEnergyGeneraFon



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PervasiveCompuFngwithAR



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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.

01/02/13 (c)Dr.RahulBanerjee,BITSPilani,INDIA 26


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What is next?

Subsequentlecturesshallintroduceyoutothefollowingtopics:

Topologiesinvolved Performance

QualityofService Reliability Security

ProtocolsandMechanismsinvolvedMethodsofSimulaFon

SengupaphysicalsystemandconfiguringitNetworkAnalysis



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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)01/02/13 (c)Dr.RahulBanerjee,BITSPilani,INDIA 28


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ArchitectureoftheInternet1of2

Brief Historical Notes:

Initiated by the US Department of Defense (DoD) through itsAdvanced Research Project Agency (ARPA) and was hence called

ARPANet.

Originally, it was a point-to-point WAN involving only four nodesacross the USA.

Original architecture that led to ARPANET has evolved over the yearsthat have passed by. In later years, ARPA / DARPA dissociated with it and allowed to this tobe blossomed into the Global Public Internet as we see it now.

Current Status: It is loosely hierarchical. Has no single body that owns it or rigidly controls it. ---Mostly run through volunteer efforts and by consensus. Runs several services, in a distributed manner, including

the immensely popular World-Wide Web.

Is helped by global cooperation including those fromgovernments and corporates apart from academia


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ArchitectureoftheInternet2of2

Currently, Internet architecture is designed for the best-effort delivery and is largely governed by the IAB of theInternet Society (ISoc). ISoc has many sub-organs which facilitate evolution and

coordinated maintenance of the Internet. IESG steers the ISoc in a general way the engineering issues

are resolved. IETF workgroups do the ground work and by a democraticprocess helps community in building up engineering solutionsthrough IETF drafts and standards (RFCs) etc.

Currently, the TCP/IP stack is the dominant protocolstack over which the Internet runs.

Keeping the needs of expansion and improvement, thisprotocol family has continually evolved over last 30+years. Current version of IP is IPv6, although IPv4 is still dominant in

use.


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WhatistheInternettoday?

Wide Area Network of variety of networks Global

Public Not transparent, as yetHybrid topology but largely hierarchical No single controller

Internet Society (ISoc) oversees, assists ---does not control

QoS, Security continue to have issues partly atleast

Web, mail, commerce, education, entertainment,sharing continue to dominate its applicationspace


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

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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(c)Dr.RahulBanerjee,BITS,Pilani,India

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A Few More Networking Terms

Repeaters / Repeater Hubs / Shared Hubs: where usually Physicallayer / level exist with L1-protocol data unit (raw bits) regeneration andonward transmission

Managed Hubs / Layer-2 Switching Hubs: where Physical and Data Linklayers / levels exist with ability to handle and deliver Layer-2-protocoldata unit (frame)

Bridges: where Physical and Data Link layers / levels exist with L2-protocol data unit (frame) processing and forwarding

Switches: where Physical and Data Link and / or Network (sometimeseven higher) layers / levels exist with Layer-2 and / or Layer-3-protocoldata unit (frame / packet) processing, switched routing / forwarding

Routers: where Physical and Data Link and Network layers / levels existwith L3-protocol data unit (packet) processing, routing and forwarding

Gateways: where two or more different networks meet and may requireprotocol / message translation capabilities

Clouds: abstraction of node connectivity in the networking context


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rames:LinkLayer(L-2)DataUnits

rame TheunitofDataasexpressedattheDataLinkLayer(Layer-2oftheHypothe0calmodelusedforinstruc0on)isconvenFonallycalledarame.

ramescantakedifferentformatsandsizesdependingupontheprotocolinquesFon ramesdoincludefieldslikesynchronizaFon,addressing,payload,control-informaFonetc.

rameorwarding Theprocessofmovingframesfromoneporttoanotherinabridgeorswitch.



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rames:actorsthatmaer!

Synchronization: Transmitter & Receiver need tobe in sync Start Delimiter: Required to mark starting bit End Delimiter: Required to mark the end bit Control Information: Information suggesting data

handling and interpretation

Error Detection / Correction / Retransmission Flow Control: Required for avoiding data loss

due to overflow at receiving end

Data Length: Needed if data-field is not of fixedsize



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LogicalViewofa10-GbpsUnit

hp://www.ovislinkcorp.co.uk/linkd.GI

7 1 6 6 246=


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SummaryofDifferencesBetweenL-2Switches,

Routers(L-3)andL-3Switches

BridgesandLayer-2switchesdividethenetworkintosegmentsormicro-segments

(apartfromhelpinginLayer-2protocol

translaFon,management,securityetc.)

Ineffect,wecansaythatLayer-2Switches/Bridgesseparatecollision

domains

Layer-2Switches/BridgescancarryoutprotocoltranslaFons

01/02/13 (c)Dr.RahulBanerjee,SDETUnit,BITS-Pilani,INDIA

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RoutersareLayer-3deviceswhohandleLayer-3packetrouFngwithinandoutsidethelocalnetwork/internetworkandthereforeeffecFvely

separatebroadcastdomainswhichendatitsdifferentnetworkinterfaces

eachofwhichcarriesaseparateSubnet-idenFfier/Subnet-address(apart

fromLayer-3protocoltranslaFon,monitoring,securityandmanagement)

Thus,ineffect,wecansaythat: RoutersSeparatebroadcastdomains(eachofsuchbroadcastdomainswhich

endatitsdifferentnetworkinterfaceseachofwhichcarriesaseparate

Subnet-idenFfier/Subnet-address)

RouterscancarryoutinteriorrouFngand/orexteriorrouFng,dependingupontheirlocaFoninthenetwork

RouterscancarryoutprotocoltranslaFons(intermsofprotocol-specificpacketformatsaswellasintermsofallowingappropriatelyformaed

selecFvedataspecifictorouFngprotocolstheymaysupport).


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Layer-3switchesaredeviceswhichcanhandleallfuncFonaliFesofLayer-2Switchesaswellasfast(oYenbasedonheader/tag/labelswitching)Layer-3

packetrouFngwithinbutnotoutsidethelocalnetwork/internetwork;and

therefore,effecFvelyseparatebroadcastdomainswhichendatitsdifferent

LANinterfaceseachofwhichcarriesaseparateSubnet-idenFfier/Subnet-

address(apartfromopFonalLayer-3protocoltranslaFon,monitoring,securityandmanagement)

Thus,ineffect,wecansaythat: L-3SwitchesSeparatebroadcastdomains(eachofsuchbroadcastdomainswhich

endatitsdifferentLANinterfaceseachofwhichcarriesaseparateSubnet-

idenFfier/Subnet-address) L-3SwitchescancarryoutfastinteriorrouFng/packet-switchingoYenbasedon

header/tag/labelswitching

Layer-3Switches,opFonally,cancarryoutprotocoltranslaFons(intermsofprotocol-specificpacketformats).


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InsideaLayer-2Switch

ElementsofaLayer-2Switch Processors(ront-endProcessorsonLineCards)for

rameRouFng

MulFpleBuffersforMulFpleQueues

SharedI/OBusorRing(1st/2ndGen.)/Switchingabric(3rdGen.)

I/PLineControllers(ILC) O/PLineControllers(OLC)

40 (c)Dr.RahulBanerjee,BITS,Pilani,India


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SomeMoreTermsofRelevance Collision Domain

The set of all stations connected to a networkwhere faithful detection of a collision can occur.

A collision domain terminates at a switch port. Late Collision

A failure of the network in which the collisionindication arrives too late in the frametransmission to be automatically dealt with by themedium access control (MAC) Protocol.

The defective frame may not be detected by allstations requiring that the application layer detectand retransmit the lost frame, resulting in greatlyreduced throughput.

CRCCyclic Redundancy Check is an error-checking

technique used to ensure the fidelity of receiveddata.

41 (c) Dr. Rahul Banerjee, BITS, Pilani, India


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WirelessCommunicaFoninWearables



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UserInterface&Sensors



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TCP/IPModel

OSI TCP/IP

Application

Presentation

Session

Transport

Network

Data Link

Physical

Application

Transport

Internet

Host-to-Network

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TCP

IP


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TCPOverview

TCP(TransmissionControlProtocol)ConnecFon-OrientedReliableProtocol

UDP(UserDatagramProtocol)ConnecFonlessUnreliableProtocol


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IPOverview

32-bitUniqueIPAddressNetworkAddressSubnetAddressHostAddress

140.112.28.XX 140.112.30.XX

Gateway

(Router)

CSC461-CN-Lectures-9-10-Feb.-1-2013

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