routing in 2016, ietf 98
TRANSCRIPT
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
Routing Indicators for IPv4
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
Routing Indicators for IPv4
But the average size of a routing advertisement is getting smaller
Routing Indicators for IPv4
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 Indicators for IPv6
Routing prefixes – growing by some 6,000 prefixes per year
Routing Indicators for IPv6
AS Numbers– growing by some 1,700 prefixes per year (which is half the V4 growth)
Routing Indicators for IPv6
More Specifics now take up more than one third of the routing table
Routing Indicators for IPv6
The average size of a routing advertisement is getting smaller
Routing Indicators for IPv6
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 - 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 - Daily Growth Rates
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!