ipv6 performance

IPv6 Performance

Geoff Huston APNIC Labs

November 2015

What are we looking at:

•  How“reliable”areIPv6connections?

•  How“fast”areIPv6connections?




Do all TCP connection attempts succeed?

Is V6 slower than V4?

The Measurement Technique

•  Embedascriptinanonlinead•  HavethescriptgenerateasetofURLstofetch

•  ExaminethepacketsseenattheservertodeterminereliabilityandRTT

Measurement Count

Measurement Count

Yes, that’s 10 M measurements per day!

Measurement Count Lo

g

Outbound SYN

Busted SYN ACK Return path

Connection Failure

What the serv

er sees is a

n

incoming SYN, but n

o

matching inco

ming ACK

server client

Compare two data sets

•  Thefirstdatasethasbeencollectedacross2011– Teredoand6to4werestillactiveasIPv6mechanisms

– LittleinthewayofotherIPv6services•  Theseconddatasethasbeencollectedacross2015– MissingcomparativeIPv4datafortheperiodSeptember–OctoberL

2011 - Measuring Failure

Why is this failure rate

for V6

so incredibly high?

2011 - Relative Connection Failure Rates

And why is the V4 relative failure rate dropping over time?

What is this spike?

2011 - Relative Connection Failure Rates

What is going on with IPv4?


ThefailurerateforV4decreasesasthevolumeofexperimentsincreases–whichimpliesthatthenumberof“nakedSYNs”beingsenttotheserversisnotrelatedtothenumberoftestsbeingperformed.AsidefromresidualIPv4failuresintheimagefetchduetodeviceresets,connectiondropouts,etc,thebulkoftherecordedfailureshereisprobablyattributabletoresearchersbotsdoingall-of-addressscanningonport80


Syn attacks?

bot scanning on port 80?

What about IPv6?

Local Miredo Relay Failures

Why is the base failure rate of all IPv6 connections sitting at 40%? This is amazingly bad!

V6 Failure Rate by Address Type

All V6 Average Teredo

6 to 4 Unicast

6to4 Failure is Local Failure

6to4failureappearstoberelatedtotwofactors:

1.  Theclient’ssitehasaprotocol41firewallfilterruleforincomingtraffic(thisispossiblymoreprevalentinAsiaPacthaninEurope)

2.  Load/delay/reliabilityissuesintheserver’schosenoutbound6to4relay(notedinthedatagatheredattheUSserver)

Evenso,the10%to20%connectionfailureratefor6to4isunacceptablyhigh!

V6 Unicast Failures January–March2012:

110,761successfulV6connectingendpoints6,227failuresThat’safailurerateof5.3%!7clientsusedfe80::linklocaladdresses7clientsusedfc00:/7ULAsourceaddresses2clientsusedfec0::/16deprecatedsitelocaladdresses16clientsused1f02:d9fc::/16Nobodyused3ffe::/16prefixes!

Data Set 2: Connection Failure in 2015

January–November201524,212,563IPv6endpoints352,919Failurerate(4.1%)

Daily IPv6 Failures

Daily IPv6 Failures

RIP Flash!

HTML5 + TLS + Mobile Devices

6to4

6,634,6606to4endpoints– 27%ofallIPv6used6to4– 9%failureratewithinthesetof6to4connections

This is still very high!

Daily IPv6 Failures

Daily IPv6 Failures

•  6to4failureratehasimprovedfrom15%-20%in2011to9%in2015

•  Teredohasallbutdisappeared•  Unicastfailurerateisbetween1.5%and4%in2015– Currentunicastfailurerateis2%

Origin AS’s with High IPv6 Failure Rates

ASFailureSamplesASNameRateAS13679 99.69%318CentrosCulturalesdeMexico,A.C.,MXAS201986 94.74%133ARPINETArpinetLLC,AMAS5511 90.68%161OPENTRANSITOrangeS.A.,FRAS20880 72.56%962TELECOLUMBUSTeleColumbusAG,DEAS17660 57.06%1,041DRUKNET-ASDrukNetISP,BTAS21107 46.64%7,564BLICNET-ASBlicnetd.o.o.,BAAS4755 40.82%316TATACOMM-ASTATACommunicationsformerlyVSNLisLeadingISP,INAS37992 40.25%159THAMMASAT-BORDER-ASThammasatUniversityinthailand,THAS28580 39.64%1,158CILNETComunicacaoeInformaticaLTDA.,BRAS17412 35.58%163WOOSHWIRELESSNZWooshWireless,NZAS52207 33.62%931TULA-ASJSC"ER-TelecomHolding",RUAS4796 32.61%414BANDUNG-NET-AS-APInstituteofTechnologyBandung,IDAS30036 30.59%17,001MEDIACOM-ENTERPRISE-BUSINESS-MediacomCommunicationsCorp,USAS9329 29.35%184SLTINT-AS-APSriLankaTelecomInternet,LKAS7477 28.10%153TEREDONN-AS-APSkyMeshPtyLtd,AUAS52888 25.79%190UNIVERSIDADEFEDERALDESAOCARLOS,BRAS28343 24.52%681TPATELECOMUNICACOESLTDA,BRAS210 22.27%247WEST-NET-WEST-UtahEducationNetwork,USAS29632 19.25%239NASSIST-ASNetAssistLLC,UAAS20857 18.10%105TRANSIP-ASTransIPB.V.,NL

Origin AS’s with Zero Failure Rates

AS3223 0.00%3,138VOXILITYVoxilityS.R.L.,ROAS16265 0.00%2,761LEASEWEB-NETWORKLeaseWebNetworkB.V.,NLAS24961 0.00%2,644MYLOC-ASmyLocmanagedITAG,DEAS39832 0.00%1,945NO-OPERAOperaSoftwareASA,NOAS2686 0.00%1,824ATGS-MMD-AS-AT&TGlobalNetworkServices,LLC,USAS33070 0.00%1,633RMH-14-RackspaceHosting,USAS55536 0.00%1,351PSWITCH-HKPACSWITCHGLOBALIPNETWORK,HKAS21191 0.00%1,210ASN-SEVERTTKClosedJointStockCompanyTransTeleCom,RUAS22584 0.00%1,165NTELOS-PCS-NtelosInc.,USAS32780 0.00%1,119HOSTINGSERVICES-INC-HostingServices,Inc.,USAS29854 0.00%1,039WESTHOST-WestHost,Inc.,USAS18144 0.00%974AS-ENECOMEnergiaCommunications,Inc.,JPAS12510 0.00%762SAP_AG_WDFSAPSE,DEAS21837 0.00%757OPERASOFTWARE-OperaSoftwareAmericasLLC,USAS13213 0.00%741UK2NET-ASUK2-Ltd,GBAS9619 0.00%672SSDSonyGlobalSolutionsInc.,JPAS19994 0.00%660RACKSPACE-RackspaceHosting,USAS32934 0.00%654FACEBOOK-Facebook,Inc.,USAS25513 0.00%639ASN-MGTS-USPDOJSMoscowcitytelephonenetwork,RUAS2614 0.00%608ROEDUNETAgentiadeAdminaReteleiNationaledeInformaticaEducatiesiCercetare,RO

Ranked by IPv6 measurement count

IPv6 Failures – Q3 2015

279,116failingIPv6addresses143,3576to4addresses118teredoaddresses92fe80::localscopeaddresses709unallocatedaddresses1,358unannouncedaddresses133,482addressesfromunicastallocatedroutedspace102,826unique/64s

What about IPv4 Connection Failures?

2011:failurerate0.2%

What about IPv4 Connection Failures?

2011:failurerate0.2%2015: 334,957,192IPv4endpoints 1,197,903ConnectionFailures(0.3%)

IPv4 Connection Failure

Missing PCAP data

Comparison

Comparison: Unicast

Comparison: Unicast

9x

It’s still not good!

IPv6UnicastFailurerate:1.8%(steady)IPv4Failurerate:0.2%(andfalling!)

Let’s dive into SYNs!

Why SYNs?

•  EveryTCPsessionstartswithaSYNhandshake

•  Itstypicallyakernelleveloperation,whichmeansthatthereislittleinthewayofapplicationlevelinteractionwiththeSYNexchange

•  Onthedownsidethereisonlyasinglesamplepointpermeasurement

Generating a comparative RTT profile

•  Foreachsuccessfulconnectioncouplet(IPv4andIPv4)fromthesameendpoint,gatherthepairofRTTmeasurementsfromtheSYN-ACKexchanges•  Usetheserver’sweblogstoassociateacouplet

ofIPv4andIPv6addresses•  UsethepacketdumpstocollectRTT

informationfromtheSYN-ACKExchange•  PlotthedifferenceinRTTinbuckets

2012 Data

IPv6 is slower IPv6 is faster

RTT Difference (in fractions of a second)

Num

ber of sam

ples (lo

g scale

)

Teredo 6 to 4 Unicast

2012 Data



Num

ber of sam

ples (lo

g scale

)

Unicast

2015 Data – November 2015



Num

ber of sam

ples (lo

g scale

) 2015 Data – November 2015

6 to 4



Num

ber of sam

ples (lo

g scale

) 2015 Data – November 2015

6 to 4 Unicast



Proportio

n of sam

ples

2015 Data CDF (using 10ms resolution)

6 to 4 Unicast



Proportio

n of sam

ples

2015 Data CDF (using 10ms resolution)

6 to 4 Unicast

18% of samples unicast IPv6 is more than 1/100 sec faster than IPv4

24% of samples unicast IPv6 is more than 1/100 sec slower than IPv4



Proportio

n of sam

ples

2015 Data CDF (using 0.1 ms resolution)

6 to 4 Unicast

Is IPv6 as “good” as IPv4?


IsIPv6asfastasIPv4?Basically,yesIPv6isfasterabouthalfofthetimeFor70%ofunicastcases,IPv6iswithin10msRTTofIPv4SotheyperformatmuchthesamerateButthat’sjustforunicastIPv6Theuseof6to4makesthisawholelotworse!


IsIPv6asrobustasIPv4?IPv4connectionreliabilitycurrentlysitsat0.2%ThebasefailurerateofUnicastV6connectionattemptsat1.8%ofthetotalV6unicastconnectionsisnotbrilliant.6to4isstillterrible!Itcouldbebetter.Itcouldbeawholelotbetter!


Ifyoucanestablishaconnection,thenIPv4andIPv6appeartohavecomparableRTTmeasurementsacrossmostoftheInternetButtheoddsofestablishingthatconnectionarestillweightedinfavourofIPv4!

That’s it!

Questions?