Routing in 2016, IETF 98

Routing in 2016

Geoff HustonChief Scientist, APNIC

Through the Routing Lens

ThereareveryfewwaystoassembleasingleviewoftheentireInternet

ThelensofroutingisoneofthewaysinwhichinformationrelatingtotheentirereachableInternetisboughttogether

Evenso,itsnotaperfectlens…

1994: Introduction of CIDR

2001: The Great Internet Boom and Bust

2005: Broadband to the Masses

2009: The GFC hits the Internet

2011: Address Exhaustion

Routing the InternetThis is a view pulled together from each of the routing peers of Route-Views

2015-2016 in detail

2015-2016 in detail

average growth trend

Route Views Peers

RIS Peers

Routing Indicators for IPv4

Routing prefixes – growing by some 54,000 prefixes per year


AS Numbers– growing by some 3,450 prefixes per year

Routing Indicators for IPv4More Specifics are still taking up one half of the routing table


But the average size of a routing advertisement is getting smaller


Address Exhaustion is now visible in the extent of advertised address space

Routing Indicators for IPv4The “shape” of inter-AS interconnection appears to be relatively steady, as the Average AS Path length has been steady through the year

AS Adjacencies (Route-Views)

6,202AS6939HURRICANE- Hurricane Electric, Inc.,US5,069AS174COGENT-174- Cogent Communications,US4,767AS3356LEVEL3- Level 3 Communications, Inc.,US2,632AS3549LVLT-3549- Level 3 Communications, Inc.,US2,397 AS7018 ATT-INTERNET4- AT&TServices, Inc., US1,959AS209CENTURYLINK-US-LEGACY-QWEST- Qwest,US1,953AS57463NETIX,BG1,691AS37100SEACOM-AS,MU1,620AS34224 NETERRA-AS,BG

19,700outof57,064ASNshave1or2ASAdjacencies(72%)

3,062ASNshave10ormoreadjacencies

22ASNshave>1,000adjacencies

What happened in 2016 in V4?

RoutingBusinessasusual– despiteIPv4addressexhaustion!

• Fromthelookofthegrowthplots,itsbusinessasusual,despitetheincreasingpressuresonIPv4addressavailability

• ThenumberofentriesintheIPv4default-freezoneisnowheadingto700,000bytheendof2017

• Thepaceofgrowthoftheroutingtableisstillrelativelyconstantat~54,000newentriesand3,400newAS’speryear• IPv4addressexhaustionisnotchangingthis!

• Instead,weareadvertisingshorterprefixesintotheroutingsystem

How can the IPv4 network continue to grow when we are running out of IPv4 addresses?

WearenowrecyclingoldaddressesbackintotheroutingsystemSomeoftheseaddressesaretransferredinwaysthatarerecordedintheregistrysystem,whileothersarebeing“leased”withoutanyclearregistrationentrythatdescribesthelessee

IPv4 Advertised Address “Age”

80% of all new addresses announced in 2010 were allocated or assigned within the past 12 months

2% of all new addresses announced in 2010 were >= 20 years ‘old’ (legacy)

2010

IPv4 Advertised Address “Age”

24 % of all new addresses announced in 2016 were allocated or assigned within the past 12 months

39 % of all new addresses announced in 2016 were >= 20 years ‘old’(legacy)

2016

IPv4: Advertised vs Unadvertised Addresses

IPv4: Unadvertised Addresses

IPv4:Assigned vs Recovered

Growth in Advertised Addresses

Change in the Unadvertised Address Pool

RIR Allocations

“recovery”

“draw down”

IPv4 in 2016

Theequivalentof1.8/8swasaddedtotheroutingtableacross2016• Approximately1.3/8swereassignedbyRIRsin2015• 0.7/8’sassignedbyAfrinic• 0.2/8swereassignedbyAPNIC,RIPENCC(Last/8allocations)

• 0.1/8swereassignedbyARIN,LACNIC

• Andanetof0.5/8’swererecoveredfromtheUnadvertisedPool

The Route-Views view of IPv6

World IPv6 Day

IANA IPv4 Exhaustion

2015-2016 in detail


Routing prefixes – growing by some 6,000 prefixes per year


AS Numbers– growing by some 1,700 prefixes per year (which is half the V4 growth)


More Specifics now take up more than one third of the routing table


The average size of a routing advertisement is getting smaller


Advertised Address span is growing at a linear rate

Routing Indicators for IPv6The “shape” of inter-AS interconnection in IPv6 appears to be steady, as the Average AS Path length has been held steady

AS Adjacencies (Route Views)

9,105outof13,197ASNshave1or2ASAdjacencies(69%)917ASNshave10ormoreadjacencies4ASNshave>1,000adjacencies

3,276AS6939HURRICANE- HurricaneElectric,Inc.,US1,607AS174COGENT-174- CogentCommunications,US1,310AS3356LEVEL3- Level3Communications,Inc.,US1,112AS37100SEACOM-AS,MU

IPv6 in 2015

• OverallIPv6InternetgrowthintermsofBGPissteadyatsome6,000routeentriesp.a.

ThisisgrowthofBGProuteobjectsis1/9ofthegrowthrateoftheIPv4network– ascomparedtotheASgrowthratewhichis1/2oftheIPv4ASnumbergrowthrate

What to expect

BGP Size Projections

FortheInternetthisisatimeofextremeuncertainty• RegistryIPv4addressrunout• Uncertaintyovertheimpactsofmarket-mediatedmovementsofIPv4ontheroutingtable

• UncertaintyoverthetimingofIPv6takeup leadstoamixedresponsetoIPv6sofar,andnoclearindicatoroftriggerpointsforchangeforthoseremainingIPv4-onlynetworks

V4 - Daily Growth Rates


V4 - Relative Daily Growth Rates

V4 - Relative Daily Growth Rates

GrowthintheV4networkappearstobeconstantatalongtermaverageof120additionalroutesperday,orsome45,000additionalroutesperyear

GiventhattheV4addresssupplyhasrunoutthisimpliesfurtherreductionsinaddresssizeinroutes,whichinturnimpliesevergreaterrelianceonNATs

IPv4 BGP Table Size Predictions

Jan2013 441,0002014 488,0002015 530,0002016 586,000 580,0002017 646,000 628,000 620,0002018 700,000 675,000 670,0002019 754,000 722,000 710,0002020 808,000 768,000 760,0002021 862,000 815,0002022 916,000

Jan2016PREDICTION

Jan2015PREDICTION

Jan2017PREDICTION


V6 - Relative Growth Rates

V6 - Relative Growth RatesGrowthintheV6networkappearstobeincreasing,butinrelativetermsthisisslowingdown.

Earlyadopters,whohavetendedtobetheV4transitproviders,havealreadyreceivedIPv6allocationandareroutingthem.ThetrailingedgeofIPv6adoptionaregenerallycomposedofstubedgenetworksinIPv4.ManyofthesenetworksappearnottohavemadeanyvisiblemovesinIPv6asyet.

Ifweseeachangeinthispicturethegrowthtrendwilllikelybeexponential.Butitsnotclearwhensuchatippingpointwilloccur

IPv6 BGP Table Size predictions

Jan2014 16,1002015 21,2002016 27,0002017 35,0002018 50,000 43,0002019 65,000 51,0002020 86,000 59,0002021 113,000 67,0002022150,000 75,000

ExponentialModelLinearModel

Range of potential outcomes

BGP Table Growth

Nothinginthesefiguressuggeststhatthereiscauseforurgentalarm-- atpresent

• TheoveralleBGP growthratesforIPv4areholdingatamodestlevel,andtheIPv6table,althoughitisgrowingatafasterrelativerate,isstillsmallinsizeinabsoluteterms

• Aslongaswearepreparedtolivewithinthetechnicalconstraintsofthecurrentroutingparadigm,theInternet’suseofBGPwillcontinuetobeviableforsometimeyet

• Nothingismeltingintermsofthesizeoftheroutingtableasyet

BGP Updates

• WhataboutthelevelofupdatesinBGP?• Let’slookattheupdateloadfromasingleeBGPfeedinaDFZcontext

IPv4 Announcements and Withdrawals

IPv4 Convergence Performance

Updates in IPv4 BGP

Thenumberofupdatesperinstabilityeventhasbeenrelativelyconstant

Whichisgood,butwhyisthishappening?

LikelycontributorstothisoutcomearethedampingeffectofwidespreaduseoftheMRAIintervalbyeBGPspeakers,andthetopologyfactors,asseenintherelativelyconstantV4ASPathLength

V6 Announcements and Withdrawals

V6 Convergence Performance

High noise components in IPv6

V6 Updated prefixes per day

V6 Updates per event

Updates in IPv6

BGPRouteUpdatesareveryunequallydistributedacrosstheprefixset– theyappeartoaffectaverysmallnumberofprefixeswhichstandoutwellabovetheaverage

Updates in IPv6

Thebusiest50IPv6prefixesaccountedfor1/2ofallBGPIPv6prefixupdates

http://bgpupdates.potaroo.net/instability/v6-bgpupd.html

Compared to IPv4

IPv6 IPv4

http://bgpupdates.potaroo.net/instability/bgpupd.htmlhttp://bgpupdates.potaroo.net/instability/v6-bgpupd.html

Updates in IPv6 BGP

IPv6routingbehaviour issimilartoIPv4behaviour:

Mostannouncedprefixesarestableallofthetime

Andasmoreprefixesareannounced,mostoftheseannouncedprefixesarehighlystable.

Butforasmallnumberofprefixesweobservehighlyunstablebehaviours thatdominateIPv6BGPupdateswhichappeartobemoreunstable(relatively)thanIPv4

Today’s State of Routing

“MostlyHarmless”

Thelevelsofgrowthofthetables,andthelevelsofgrowthofupdatesinBGPdonotposeanyimmediateconcerns

Thetrendsarepredictableandsteady,sonetworkoperatorscanplanwellinadvanceforthecapacityofroutingequipmenttomeettheirfutureneeds

But:

Theadvancedlevelsofinstabilitybyasmallnumberofnetworksarealwaysannoying!Howcanwepreventthesehighlyunstableprefixes?

That’s it!

Date post:	07-Apr-2017
Category:	Internet
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