measuring ipv6 performance - ripe 73in ipv6 we are seeing path asymmetry, with outbound packets...

Measuring IPv6 Performance

Geoff HustonAPNIC Labs

What are we looking at:

• How“reliable”areIPv6connections?

• How“fast”areIPv6connections?

What are we looking at:

• How“reliable”areIPv6connections?

• How“fast”areIPv6connections?

The Measurement Technique

• Embedascriptinanonlinead• HavethescriptgenerateasetofURLstofetch• ExaminethepacketsseenattheservertodeterminereliabilityandRTT

How We Measure

Weuseanonlineadtopresentasequenceofsmallfetchestotheuser’sbrowser

How We Measure

ThesequenceoftestsisusedtotestanumberoftypesofactionsincludingfetchesofIPv4,IPv6andDualstack

How We MeasureWeusetcpdump torecordallpacketactivityattheexperiment’sservers

How Much do We Measure?

What are we looking at:

• How“reliable”areIPv6connections?

• How“fast”areIPv6connections?

Outbound SYN

Busted SYN ACKReturn path

What we see: Connection Failure

serverclient

IPv4 Connection Failure

0.22%FailureRate

IPv4 Failures

• IPv4failuresarearound1in500• AndweareprettysureitsNOT:– Auto-tunnelling– LousyCPEfirmware– Strangefirewallfilters

• Sowhatisthereasonforthisresidualasymmetricfailurerate?• Isitasymmetricroutingconnectivity?

Daily IPv6 Failures

6to4failure:around10%

AverageIPv6failure:around2%

UnicastIPv6failure:around1.5%

Daily IPv6 Failures

Unicast IPv6 shows moderate reliability

1.5%FailureRate

IPv6 Failures

• 1.5%failureforunicastV6isstillunacceptable!• Whyisthishappening?– Auto-tunnelling?– LousyCPEfirmware?– Strangefirewallfilters?– Asymmetricrouting

Is IPv6 failure uniformly distributed?

Is IPv6 failure uniformly distributed?

V6 Failure by Country

V6 Failure by Network

A cautionary note

• Theseare“singleshot”measurementsratherthansustainedrepeatedtest,sothereissomenoisecomponenthere

• Itsalsolikelythatconnectionfailureisrelatedtoconsumerequipmentratherthannetwork-levelfailure,asanetworklevelfailurewouldconventionallygiveafailureratecloserto100%

What are we looking at:

• How“reliable”areIPv6connections?

• How“fast”areIPv6connections?

Let’s look at TCP SYNs

Let’s look at TCP SYNs

1 RTT interval

Why SYNs?

• EveryTCPsessionstartswithaSYNhandshake• Itstypicallyakernelleveloperation,whichmeansthatthereislittleinthewayofapplicationlevelinteractionwiththeSYNexchange

• Onthedownsidethereisonlyasinglesamplepointpermeasurement

Generating a comparative RTT profile

• Foreachsuccessfulconnectioncouplet(IPv4andIPv4)fromthesameendpoint,gatherthepairofRTTmeasurementsfromtheSYN-ACKexchanges• Usetheserver’sweblogstoassociateacoupletofIPv4andIPv6addresses

• UsethepacketdumpstocollectRTTinformationfromtheSYN-ACKExchange

• UseIPv6RTT– IPv4RTTasthemetric

An Example of Path Divergence$traceroutefromSingaporetoCanberra,IPv4tracerouteto202.158.xxxx.yyy,30hopsmax,60bytepackets1103.3.60.30.672ms0.796ms0.899ms2139.162.0.90.754ms0.708ms0.732ms3te0-1-0-21.br03.sin02.pccwbtn.net1.697ms0.760ms0.726ms4ntt.fe3-18.br01.sin02.pccwbtn.net69.526ms69.644ms69.754ms5ae-10.r20.sngpsi05.sg.bb.gin.ntt.net60.702ms68.474ms68.469ms6ae-8.r22.snjsca04.us.bb.gin.ntt.net168.447ms168.532ms168.138ms7ae-19.r01.snjsca04.us.bb.gin.ntt.net167.489ms170.665ms178.832ms8xe-0-8-0-21.r01.snjsca04.us.ce.gin.ntt.net330.084ms323.556ms329.772ms9xe-1-0-1.pe1.msct.nsw.aarnet.net.au330.020ms323.738ms334.474ms10et-3-3-0.pe1.rsby.nsw.aarnet.net.au327.788ms334.157ms328.199ms11138.44.161.6323.644ms319.455ms323.563ms12202.158.xxx.yyy319.885ms333.933ms325.014ms

$traceroute from CanberratoSingapore,IPv4traceroute to139.162.xxx.yyy,64hops max,52byte packets1202.158.x.y0.682ms0.388ms0.313ms2xe-5-0-4-205.pe1.actn.act.aarnet.net.a0.721ms0.828ms0.674ms3et-0-3-0.pe1.rsby.nsw.aarnet.net.au4.548ms4.733ms4.533ms4et-7-1-0.pe1.brwy.nsw.aarnet.net.au4.734ms5.418ms4.745ms5et-0-3-0.pe1.bkvl.nsw.aarnet.net.au5.117ms5.512ms5.524ms6xe-0-0-0.bb1.b.sea.aarnet.net.au148.017ms148.019ms148.131ms7ge3-0.cr02.sea01.pccwbtn.net(206.81.80.13)148.469ms148.059ms148.429ms8tenge0-2-0-14.br03.sin02.pccwbtn.net319.435ms325.053ms319.117ms9tenge0-2-0-15.br03.sin02.pccwbtn.net319.257ms332.560ms323.415ms10linode.te0-1-0-21.br03.sin02.pccwbtn.net323.723ms323.627ms323.587ms11139.162.aaa.bbb334.609ms347.243ms347.220ms12139.162.xxx.yyy325.186ms338.209ms325.603ms

IPv4

We are seeing path symmetry, bouncing off the US West Coast

An Example of Path Divergence

$traceroutefromSingaporetoCanberra,IPv6traceroute6to2001:388:1000:110:e4d:e9ff:x:y,30hopsmax,80bytepackets12400:8901::5287:89ff:fe40:9fc10.897ms0.912ms1.051ms22400:8901:1111::10.851ms0.827ms0.792ms32001:cb0:2102:2:f::10.364ms0.333ms0.516ms42001:cb0:2102:2:f::10.502ms0.461ms0.431ms52001:cb0:21f0:1:17::22.512ms2.176ms3.445ms62001:cb0:21f0:1:17::22.354ms2.382ms1.238ms710gigabitethernet3-5.core1.sin1.he.net1.080ms1.034ms1.020ms810ge1-5.core1.tyo1.he.net88.053ms10ge1-16.core1.hkg1.he.net39.369ms10ge1-5.core1.tyo1.he.net88.084ms

910ge1-5.core1.tyo1.he.net88.157ms100ge8-1.core1.sea1.he.net192.408ms192.642ms

10100ge8-1.core1.sea1.he.net192.631ms192.608ms196.154ms11xe-1-0-1.pe2.brwy.nsw.aarnet.net.au214.176ms186.238ms213.061ms12et-3-1-0.pe1.brwy.nsw.aarnet.net.au211.298ms211.300ms214.200ms13et-1-1-0.pe1.rsby.nsw.aarnet.net.au211.492ms211.359ms211.427ms14et-0-3-0.pe1.actn.act.aarnet.net.au213.332ms211.458ms211.476ms152001:388:1000:110:e4d:e9ff:x.y213.274ms213.199ms213.169ms

$traceroutefromCanberratoSingapore,IPv6traceroute6to2400:8901::f03c:91ff:a:b)64hopsmax,12bytepackets12001:388:1000:110::x:y 0.808ms0.899ms1.586ms2xe-5-0-4-205.pe1.actn.act.aarnet.net.au1.633ms0.646ms0.578ms3et-0-1-0.pe1.dksn.act.aarnet.net.au0.682ms0.649ms0.694ms4et-5-3-0.pe1.crlt.vic.aarnet.net.au8.072ms8.086ms8.049ms5et-5-1-0.pe1.wmlb.vic.aarnet.net.au8.116ms8.055ms8.073ms6et-0-3-0.pe1.adel.sa.aarnet.net.au17.790ms16.984ms17.036ms7et-1-1-0.pe1.prka.sa.aarnet.net.au17.080ms17.152mset-0-3-0.pe1.eper.wa.aarnet.net.au43.319ms

8et-0-3-0.pe1.knsg.wa.aarnet.net.au43.357ms43.443ms43.353ms9gigabitethernet-5-1-0.bb1.b.per.aarnet.net.au43.849ms43.919ms43.850ms10so-0-0-0.bb1.a.sin.aarnet.net.au92.219ms92.275ms92.189ms11as6939.singapore.megaport.com212.347ms212.426ms212.471ms12***132400:8901:1110::2213.924ms213.904ms213.717ms142400:8901::f03c:91ff:a:b213.954ms213.393ms213.726ms

IPv4 – IPv6

In IPv6 we are seeing path asymmetry, with outbound packetsCrossing an Indian Ocean cable, and return packets bouncingoff the US West Coast – the IPv6 RTT is 112 ms smaller than the IPv4 RTT

Global Results

On average IPv6 is showing 20ms – 40ms slower that IPv4

Global Results

Mean Standard Deviation per day of these measurements

Number of sample points per day

RTT Diff Distribution

120 day average

IPv6Faster(ms) IPv4Faster(ms)

RTT Diff by Country

RTT Diff by Network

European RegionV4 faster nets

European RegionV6 faster nets

IPv6 in Spain:

Largest ISPs

IPv6 in Spain:

IPv6 ISPs

IPv6 in Spain – RTT Diff distribution

Germany

German IPv6 ISPs

RTT Diff for DTAG – AS3320

Is IPv6 as “good” as IPv4?

Is IPv6 as “good” as IPv4?

IsIPv6asfast asIPv4?Basically,yesIPv6isfasterabouthalfofthetimeFor75%ofunicastcases,IPv6iswithin10msRTTofIPv4Sotheyperformatmuchthesamerate

(Butthat’sjustforunicastIPv6- theuseof6to4makesthisawholelotworse!)

Is IPv6 as “good” as IPv4?

IsIPv6asrobustasIPv4?IPv4averageconnectionreliabilitycurrentlysitsat0.2%

ThebaseaveragefailurerateofUnicastV6connectionattemptsat1.5%ofthetotalV6unicastconnectionsisnotbrilliant.(6to4isterribleatthis!)

Itcouldbebetter.

Itcouldbeawholelotbetter!

Is IPv6 as “good” as IPv4?

Ifyoucanestablishaconnection,thenIPv4andIPv6appeartohavecomparableRTTmeasurementsacrossmostoftheInternet

ButtheoddsofestablishingthatconnectionarestillweightedinfavourofIPv4!

That’s it!

http://stats.labs.apnic.net/v6perf