tcp/icn: carrying tcp over content centric and named data ... · unaltered tcp/ip stack and...

TCP/ICN:CarryingTCPoverContentCentricandNamedDataNetworks

IlyaMoiseenkoCiscoSystems

DaveOranCiscoSystems

Outline

I. IntroductionII. Design– Basicfetchingproxy– Reliableprefetchingproxy– Unreliableprefetchingproxy

III. EvaluationIV. Conclusions

2

3

I.Introduction

WhyBother?YoucouldjustrunDual-Stackin”Ships-in-the-night”mode.But… amajorattractionofICNissimplificationandperformanceinenvironmentsnotfriendlytoIP:• Mobileedge– eliminatetunnels,respondmorequicklytomobilityevents,temporalcachingattheedgeforbettererrorcontrol

• IoT – Muchsmallercodefootprint,betterintegrationwithradioprotocols,lowerbackgroundchatterthanIP

4

High-levelgoals

1. UnalteredTCP/IPstackandapplications2. PreserveTCPend-to-endsemantics– Split-TCPfunctionalitycanbeaddedafterwards

3. Pulldatabetweenproxies(i.e.don’trequiredatapushinInterests)

4. CompatibilitywithbothCCNandNDN5. Minimizeoverhead

5

Non-goals

1. SupportofUDPorothertransportprotocols2. Heterogeneousaddressingandrouting– Eachproxyownsaroutablenameprefix– DonotproposeIPaddr <->nameprefixmapping

3. PathMTU-discoveryandfragmentation– Assumestandard1500-byteTCPMSSandupto

9000bytesICNDatamessages

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II.Design

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Mainchallenges

• HowtoreconciletheTCP/IPpushmodelwiththeICNpullmodel?

• Howtominimizeinflationofmessagecountandmessagesizes?

• HowmuchdoesthetranslationfunctionneedtounderstandtheTCPstatemachine?

• HowtomarrytheICNandTCPcongestionandflowcontrolmodels?

8

DesignalternativesforTPC/ICNProxies

• Wedesignedandevaluatedthreeapproaches:– Simpleone-to-onemappingofTCPmessagestoICNexchanges

– TracktheTCPstatemachineintheproxiestoprovidereliabilityovertheICNsegmentofthepath

–MapTCPDatatoICNDatausinganunreliableinter-proxychannel

• Connectionstatemachinesameforallthree–differonlyinthedataphase

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Sharedparts

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TCPconnectionsetup

Interest: /<routable prefix>/<TCP/IP headers>/<nonce>

SYN flag

Interest: /<routable prefix>/<TCP/IP headers>/<nonce> SYN, ACK flags

Interest: /<routable prefix>/<TCP/IP headers>/<nonce> ACK flag

/verizon

/att

/verizon


FIN flag



Interest: /<routable prefix>/<TCP/IP headers>/<nonce> FIN flag

/verizon

/att

/att

/verizon

TCPconnectionteardown

Basicfetching

• DataencapsulatesaTCPsegmentcarryingpayload/[forward-proxy-prefix]/[TCP-4-tuple]/[TCP-sequence-number]/[Wraparound-number]

• InterestencapsulatesanemptyTCPsegment/[reverse-proxy-prefix]/[TCP-IP-headers]/[nonce]

• Slow:2xRTT,2xpackets

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Forward proxy

Interest with TCP/IP headers

Reverse proxy

Data carrying TCP payload

1"

2"

3"

4" Interest pulling data

5"

6"

Data"cache"

Unidirectional TCP flow

TCP$data$$segment$

TCP$data$$segment$

TCP$$ACK$

TCP$$ACK$


TCP receiver TCP sender

ReliableprefetchingDatasequencingisindependentfromTCPsequencing

– ImpossibletopredictTCPsequencenumberprogression

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Interest: /<routable prefix>/<connection id>/<sequence#> TCP 4 tuple


SEQ # 376523 ACK # 1225142 TCP/IP:

SEQ # 376523 ACK # 1225142

TCP/IP: SEQ # 1223682 ACK # 376523

TCP/IP: SEQ # 1225142 ACK # 376523

Forward proxy


130

Interest: /<routable prefix>/<connection id>/<sequence#> TCP 4 tuple 129

Data: /<routable prefix>/<connection id>/<sequence#> TCP 4 tuple 129

Data: /<routable prefix>/<connection id>/<sequence#> TCP 4 tuple 130

Reliableprefetching

• ReverseproxytransmitsanInterestpriortoTCPsegmentarrivalattheforwardproxy– Enforcesreliability

• Forwardproxyadvertisesapprox.TCPcwnd size• Faster,butunstable.Alotofstateintheproxy.Otherissues.

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Forward proxy Reverse proxy

1"

2"

3"

4"

6"

Reliable"consumer"

Interest"queue"

cwnd"adver:ser"

Data"queue"+"cache"TCP$data$$segment$

TCP$data$$segment$

5"

TCP$$ACK$

TCP$$ACK$

Interest per each RTT

Interest pipelining w.r.t cwnd

Data carrying TCP segment



TCP sender TCP receiver

UnreliableprefetchingTime-delayednaming

– DatanamesmatchTCPsequencenumbersdeliveredoneRTTago

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SEQ # 376523 ACK # 1222222


SEQ # 376523 ACK # 1225142

TCP/IP: SEQ # 376523 ACK # 1222222

TCP/IP: SEQ # 1223682 ACK # 376523

TCP/IP: SEQ # 1225142 ACK # 376523 Data: /<routable prefix>/<TCP/IP headers>/<nonce>

SEQ # 376523 ACK # 1222222

Forward proxy


Unreliableprefetching

• InterestsencapsulatingACKsprefetch newTCPsegments– NotenoughACKsduetodelayedACKTCPmechanism– PackagemultipleTCPsegmentsinasingleDatamessage

• NoadditionalreliabilityinICNprotocol• Fast.ComparabletoTCP/IP(cubic).Scalable.

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Forward proxy Reverse proxy

1"2"3"

4" 6"

Interest"queue"

TCP"queue"

TCP$data$$segment$

TCP$data$$segment$

5"

TCP$$ACK$

TCP$$ACK$


Data carrying multiple TCP data segments


TCP sender TCP receiver

Unreliableprefetching

Aproblemoffull-duplexTCPconnection:TCPpiggybacksACKsinthedatasegments-->noInterestsaresentbytheproxies

• Aproxydetectsfull-duplexbyanalyzingACK#• GeneratesInterestsonitsown– Fixedprobability(e.g.50%=every2nd segment)– FunctionofACK#progression

16

17

III.Evaluation

Evaluation

TCPcubicoverICNvs.TCPcubicoverIP

• NDNsim• Proofofconcept*niximplementation

– Unreliableprefetching18

TCP client IP forwarder IP forwarder IP forwarder TCP server

TCP client TCP server ICN forwarder TCP/ICN proxy

TCP firewall

ICN forwarder ICN forwarder TCP/ICN proxy

TCP firewall

Flowcompletiontime

19

TCP cubicUnreliable prefetching

Reliable prefetchingBasic fetching

0

0e+00

2e+07

4e+07

0 200 400 600

Time (ms)

TCP

sequ

ence

num

ber

a

a

a

a

Basic fetching

Reliable prefetching

TCP cubic

Unreliable prefetching

Unreliableprefetchingis10%slowerthanTCP/IP

TCPretransmissions

20



Basic fetching

0

0

500

1000

1500

2000

0 200 400 600

Time (ms)

Tota

l num

ber o

f TC

P re

trans

mis

sion

s (p

acke

ts)

a

a

a

a

Basic fetching


TCP cubic


TCPcongestionwindowsize

21

TCP cubic



Basic fetching

0

0

20000

40000

60000

0 200 400 600

Time (ms)

Cw

nd (b

ytes

)

a

a

a

a

Basic fetching


TCP cubic


TCPretransmissiontimeout

22



Basic fetching

0

500

1000

1500

2000

0 200 400 600

Time (ms)

RTO

(ms)

a

a

a

a

Basic fetching


TCP cubic


Flowfairnessandcompletiontime

23

50

100

150

200

1 10 100 500

TCP flow size (Mb)

TCP

flow

com

plet

ion

time

(sec

)

TCP/ICN

TCP/IP• Unreliable

prefetching• tcpperf tool+

proxyPoC• 10competing

unidirectionalflows

• Within5%differencewithTCP/IP

• Fair

Beyondsynthetictests

TLSrequiresadditionalaccommodations– InjectextraInterestsatTCPconnectionsetupphasetofetchTLSserverhellomessages

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Webbrowser

WebserverICNforwarderTCP/ICNproxyTCPfirewall

ICNforwarder ICNforwarderTCP/ICNproxyTCPfirewall

Conclusions

• WecanrunmanyInternetapplicationswithoutIP

• TCPishighlyoptimizedforIP– ButitworkssurprisinglywelloverICN!

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Q/A

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tcp/icn: carrying tcp over content centric and named data ... · unaltered tcp/ip stack and...

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