professor yashar ganjali department of computer...

ProfessorYasharGanjaliDepartmentofComputerScienceUniversityofToronto

[email protected]://www.cs.toronto.edu/~yganjali

CSC2229- Software-DefinedNetworking 2UniversityofToronto– Winter2017

Today• Outline

� Whatthiscourseisabout

• Logistics� Coursestructure,evaluation� Whatisexpectedfromyou� Whatyouwanttoknow

• Overview� Packetswitchingsystems� Software-DefinedNetworking


CSC229:Software-DefinedNetworking• Graduatelevelcourse

� IntroductiontoSoftware-DefinedNetworking(SDN)� SDNchallengesandopportunities

� Coursecomponents� Lectures� Researchpapers� Researchproject

• Theory+Practice� Switchingsystemsaresimpleenoughforustoprovesomethingaboutthem

� Yettheyarecomplexenoughtoworkinpractice


Outline– PartI� Introduction

� Packetswitchsystems� EvolutionoftheInternet,andInternetrouters� Basicarchitecturalcomponents� Someexamplearchitectures

� Software-DefinedNetworking� Innovationincomputernetworks� Controlvs.dataplane


Outline– PartII� SDNChallengesandOpportunities

� Controllerandswitchdesign� Reliability,efficiency,andscalability� Architecture� Programming,correctness,anddebugging� SDNsecurity� Newabstractions,statemanagement� Networkservices� Networkfunctionvirtualization� Networkoptimization


Logistics� Officehours

� Tue.12PM- 1PM,BA5238� Orbyappointment

� Coursewebpage� http://www.cs.toronto.edu/~yganjali/courses/csc2229/� Pleasecheckregularlyforannouncements.

� Classmailinglist� Basedone-mailaddressyouhavedefinedonACORN.� Sendmeane-mailifyouhaven’treceivedawelcomemessagefromthatlist.

� Pleasepost(course-related!)questionstothislist.


Logistics� Prerequisites

� Anyintroductorycourseonnetworking� Algorithms� Basicprobabilitytheory

� Papers� Willbelistedonclasswebpage� PleasereadsuggestedpapersBEFOREclass

Logistics� Grading

� Activeparticipationinclassanddiscussions:10%� Paperpresentations:30%� Finalproject:60%

� Proposal:5%- 1-2pages� Intermediatereport:10%- 3pages� Presentation:15%- Lastweekofclasses� Finalreport:30%- 6pages

� Deadlines� 5%markdeductionforeachdayofdelay,upto4days.� Exception:finalreportdeadlineishard.



Logistics� FinalProject

� Groupsofthreestudents� Projecttopic

� Choosefromtheofferedlist;or� Talktomeanddefineyourown


Logistics� AcademicIntegrity

� Allsubmissionsmustpresentoriginal,independentwork.

� Wetakeacademicoffensesveryseriously.� Pleaseread

� “Guidelineforavoidingplagiarism”http://www.cs.toronto.edu/~fpitt/documents/plagiarism.html� “Adviceaboutacademicoffenses”http://www.cs.toronto.edu/~clarke/acoffences/

Logistics� AccessibilityNeeds

� TheUniversityofTorontoiscommittedtoaccessibility.Ifyourequireaccommodationsorhaveanyaccessibilityconcerns,pleasevisithttp://studentlife.utoronto.ca/accessibility assoonaspossible.



Acknowledgements� Specialthanksto:

� Prof.NickMcKeown,StanfordUniversity� Prof.BalajiPrabhakar,StanfordUniversity� Prof.JenniferRexford,PrincetonUniversity� Prof.NickFeamster,PrincetonUniversity


Questions?

Whatelsedoyouliketoknowaboutthiscourse?


IntroductiontoPacketSwitching� Background

� Whatisarouter?� Routerarchitecture

� Packetprocessinginrouters� IPaddresslookup� Packetbuffering� Switching

� Routerarchitectures� Theevolution� Software-DefinedNetworking


R3

A

B

C

R1

R2

R4 D

E

FR5

R5FR3ER3DNextHopDestination

WhatisRouting?


WhatisRouting?

R3

A

B

C

R1

R2

R4 D

E

FR5

R5FR3ER3DNext HopDestination

16 3241

Data

Options(ifany)

DestinationAddress

SourceAddress

HeaderChecksumProtocolTTL

FragmentOffsetFlagsFragmentID

TotalPacketLengthT.ServiceHLenVer

20bytes


WhatisRouting?

A

B

C

R1

R2

R3

R4 D

E

FR5


PointsofPresence(POPs)

A

B

C

POP1

POP3POP2

POP4 D

E

F

POP5

POP6 POP7POP8

WhereHighPerformanceRoutersareUsed


R10 R11

R4

R13

R9

R5R2

R1 R6

R3 R7

R12

R16R15

R14

R8

(2.5Gb/s)

(2.5Gb/s)(2.5Gb/s)

(2.5Gb/s)


WhataRouterLooksLikeCiscoGSR12416 JuniperM160

6ft

19”

2ft

Capacity: 160Gb/sPower: 4.2kW

3ft

2.5ft

19”

Capacity: 80Gb/sPower: 2.6kW


BasicArchitecturalComponentsofanIPRouter

ControlPlane

Data-pathper-packetprocessing

SwitchingForwardingTable

RoutingTable

RoutingProtocols


PacketSwitching– SimpleRouterModel

R1Link1

Link2

Link3

Link4

Link1,ingress Link1,egress




ChooseEgress

ChooseEgress

ChooseEgress

ChooseEgress

“4”

“4”


Per-packetProcessinginanIPRouter1.Acceptpacketarrivingonanincominglink.2.Lookuppacketdestinationaddressintheforwardingtable,toidentifyoutgoingport(s).

3.Manipulatepacketheader:e.g.,decrementTTL,updateheaderchecksum.

4.Sendpackettotheoutgoingport(s).5.Bufferpacketinthequeue.6.Transmitpacketontooutgoinglink.


GenericRouterArchitecture

LookupIPAddress

UpdateHeader

HeaderProcessingData Hdr Data Hdr

~1MprefixesOff-chipDRAM

AddressTable

IPAddress NextHop

QueuePacket

BufferMemory

~1MpacketsOff-chipDRAM


LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

Data Hdr

Data Hdr

Data Hdr

BufferManager

BufferMemory

BufferManager

BufferMemory

BufferManager

BufferMemory

Data Hdr

Data Hdr

Data Hdr


WhyareFastRoutersDifficulttoMake?� It’shardtokeepupwithMoore’sLaw:

� Thebottleneckismemoryspeed.� MemoryspeedisnotkeepingupwithMoore’sLaw.

�Moore’sLawistooslow:� RoutersneedtoimprovefasterthanMoore’sLaw.



RouterPerformanceExceedsMoore’sLaw� Growthincapacityofcommercialrouters:

� Capacity1992~2Gb/s� Capacity1995~10Gb/s� Capacity1998~40Gb/s� Capacity2001~160Gb/s� Capacity2003~640Gb/s� Capacity2007~4Tb/s� Capacity2010~16Tb/s� 2017...?

Averagegrowthrate:2x/18months.



LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

BufferManager

BufferMemory

BufferManager

BufferMemory

BufferManager

BufferMemory

LookupIPAddress

AddressTable

LookupIPAddress

AddressTable

LookupIPAddress

AddressTable

IPAddressLookup�Whyit’sthoughttobehard:

1. It’snotanexactmatch:it’salongestprefixmatch.2. Thetableislarge:about700,000entriestoday,andgrowing.

3. Thelookupmustbefast:about30nsfora10Gb/sline.



IPLookupsfindLongestPrefixes

128.9.16.0/21 128.9.172.0/21

128.9.172.0/24

0 232-1

128.9.0.0/16142.12.0.0/1965.0.0.0/8

128.9.16.14

Routinglookup: Findthelongest matchingprefix(akathemostspecificroute)amongallprefixesthatmatchthedestinationaddress.


AddressTablesareLarge

Source:http://www.cidr-report.org/


LookupsMustbeFast

40Bpackets(Mpkt/s)

LineYear

Year Line Rate 40B Packets (Mpkt/s)

1997 622Mb/s 1.94

1999 2.5Gb/s 7.81

2001 10Gb/s 31.25

2003 40Gb/s 125

2005 100Gb/s 312


LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

QueuePacket

BufferMemory

QueuePacket

BufferMemory

QueuePacket

BufferMemory

BufferManager

BufferMemory

BufferManager

BufferMemory

BufferManager

BufferMemory



FastPacketBuffers

Example:40Gb/spacketbufferSize=RTT*BW=10Gb;40bytepackets

WriteRate,R

1packetevery8ns

ReadRate,R

1packetevery8ns

BufferManager

BufferMemory

UseSRAM?+ fastenoughrandomaccesstime,but

- toolowdensitytostore10Gbofdata.

UseDRAM?+highdensitymeanswecanstoredata,but- tooslow(50nsrandomaccesstime).



LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

QueuePacket

BufferMemory

QueuePacket

BufferMemory

QueuePacket

BufferMemory

Data Hdr

Data Hdr

Data Hdr

1

2

N

1

2

N

N timeslinerate

N timeslinerate



LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

QueuePacket

BufferMemory

QueuePacket

BufferMemory

QueuePacket

BufferMemory

Data Hdr

Data Hdr

Data Hdr

1

2

N

1

2

N

Data Hdr

Data Hdr

Data Hdr

Scheduler


0% 20% 40% 60% 80% 100%Load

Delay

ARouterwithOutputQueues

Thebestthatanyqueueingsystemcanachieve.


0% 20% 40% 60% 80% 100%Load

Delay

ARouterwithInputQueuesHeadofLineBlocking


2 2 58%- »


HeadofLineBlocking


VirtualOutputQueues


0% 20% 40% 60% 80% 100%Load

Delay

ARouterwithVirtualOutputQueues




LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

LookupIPAddress

UpdateHeader

HeaderProcessing

AddressTable

QueuePacket

BufferMemory

QueuePacket

BufferMemory

QueuePacket

BufferMemory

Data Hdr

Data Hdr

Data Hdr

1

2

N

1

2

N

N timeslinerate

N timeslinerate


RouteTableCPU Buffer

Memory

LineInterface

MAC

LineInterface

MAC

LineInterface

MAC

Typically<0.5Gb/saggregatecapacity

SharedBackplane

FirstGenerationRouters


RouteTableCPU

LineCard

BufferMemory

LineCard

MAC

BufferMemory

LineCard

MAC

BufferMemory

FwdingCache

FwdingCache

FwdingCache

MAC

BufferMemory

Typically<5Gb/saggregatecapacity

SecondGenerationRouters


LineCard

MAC

LocalBufferMemory

CPUCard

LineCard

MAC

LocalBufferMemory

SwitchedBackplane

FwdingTable

RoutingTable

FwdingTable

Typically<50Gb/saggregatecapacity

ThirdGenerationRouters


SwitchCore Linecards

Opticallinks

100sofmetres

0.3- 10Tb/sroutersindevelopment

FourthGenerationRouters/SwitchesOpticsinsidearouterforthefirsttime

SoftwareDefinedNetworks


Data Plane

Control Plane

Data Plane

Control PlaneData Plane

Control Plane

Data Plane

Control Plane

SoftwareDefinedNetworks– Cont’d


Controller

OpenFlow SwitchPC

Data Plane

Data Plane

Data Plane

Data Plane

FinalComments/Questions�Whatotherlineratefunctionalitiescanyouthinkof(otherthanpacketforwarding)?� Aretheyperformancebottleneckintoday’snetworks?� Howwouldtheyevolveovertime?� Dotheybelongondatapath?

� Controlandmanagementcomplexity� Whatcontrolfunctionalitiesdowehaveinnetworkstoday?

� Howdowemanagethose?� Whatcanwedotosimplifythis?


professor yashar ganjali department of computer...

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