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IPv4 Address Allocation Trends

J. Scott MarcusChief Technology Officer (CTO)

May 22, 2001

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IPv4 Address Allocation Trends

• AS number exhaustion - the RIRs recognize the need for forecasting

• IPv4 allocation and usage trends• The McFadden/Holmes Report

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Exponential Growth of Autonomous System (AS) numbers

R2 = 0.9957

0

10000

20000

30000

40000

50000

60000

70000

80000

10/0

1/1

996

10/0

1/1

997

10/0

1/1

998

10/0

1/1

999

10/0

1/2

000

10/0

1/2

001

10/0

1/2

002

10/0

1/2

003

10/0

1/2

004

10/0

1/2

005

AS

Num

bers

(A

SN

s)

ASNs to Oct2000

ASNs since Oct2000

Expon. (ASNs to Oct2000)

Source: Scott Marcus, Genuity

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Exponential vs Quadratic (Bates Data)

y = 6E-14e0.0011x

R2 = 0.9957

y = 0.002x2 - 138.37x + 2E+06

R2 = 0.9962

0

5000

10000

15000

20000

25000

10/0

1/19

96

01/0

1/19

97

04/0

1/19

97

07/0

1/19

97

10/0

1/19

97

01/0

1/19

98

04/0

1/19

98

07/0

1/19

98

10/0

1/19

98

01/0

1/19

99

04/0

1/19

99

07/0

1/19

99

10/0

1/19

99

01/0

1/20

00

04/0

1/20

00

07/0

1/20

00

10/0

1/20

00

01/0

1/20

01

04/0

1/20

01

07/0

1/20

01

10/0

1/20

01

01/0

1/20

02

04/0

1/20

02

07/0

1/20

02

10/0

1/20

02

01/0

1/20

03

Act

ive

AS

es (

Cle

an)

ASNs to Oct2000

ASNs since Oct2000

Expon. (ASNs to Oct2000)

Poly. (ASNs to Oct2000)

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Chicken Little was Wrong!

• This is far simpler to remedy than IPv4 address exhaustion, because– the solution need not impact end systems (hosts);

– the solution need not impact DNS; and

– the solution need not impact routers unless they speak BGP-4.

• Any solution is complicated by the need for backward compatibility and phased migration.

• Time until exhaustion is nonetheless sufficient to architect, design, implement and deploy solutions.

• Cisco and Juniper are reportedly well into implementation.

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BGP Table Growth since 1989

Route Table Bloat - a Different Problem

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The RIRs Recognize the Need for Forecasting

• Continuing need to further refine projections.• Need for forward-looking proactive forecasting on a

regular basis not only for AS numbers, but also for route table entries and IPv4/IPv6 addresses.

• Forecasting needs to incorporate allocation data from all three RIRs (APNIC, ARIN, RIPE NCC).

• Forecasting needs to be institutionalized by the RIRs themselves, with data readily available to independent researchers.

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The Team

• Assembled by ARIN– Frank Solensky Gotham Networks– kc claffy CAIDA– Scott Marcus Genuity

• Active contributions and support by APNIC and RIPE NCC

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Goals (and Non-Goals) for RIR Team

• Formally and regularly:– Gather address deployment data from RIRs– Perform statistical analysis– Make allocation data available for independent analysis

• Non-goals:– ‘Blue sky’ theorizing– Estimating NAT utilization (for now)

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Annual IPv4 Address Allocation

100

200

300

400

500

600

1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

IPv4

Ad

dre

ss

es

(m

illio

ns

)

RIPE

ARIN

APNIC

Annual IPv4 Allocations

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Cumulative IPv4 Addresses Allocated

.

.5

1.

1.5

2.

2.5

1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001

IPv4

Add

ress

es (b

illio

ns)

RIPE

ARIN

APNIC

Cumulative IPv4 Allocations

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y = 6E+06x - 5E+09

R2 = 0.9329

1.0

1.5

2.0

2.5

3.0

3.5

4.0

1991

1996

2001

2006

2011

2016

2021

2026

IPv4 Address Allocations: Linear Fit

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Address Allocations: Logistic Fit

1.0

1.5

2.0

2.5

3.0

3.5

4.0

1991

1996

2001

2006

2011

2016

2021

2026

y= _____1.938 E + 9____1+Exp(-0.33x - 0.226)

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A Closer Look - Logistic Curve

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

Jun-

91

Dec-91

Jun-

92

Dec-92

Jun-

93

Dec-93

Jun-

94

Dec-94

Jun-

95

Dec-95

Jun-

96

Dec-96

Jun-

97

Dec-97

Jun-

98

Dec-98

Jun-

99

Dec-99

Jun-

00

Dec-00

Jun-

01

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Addresses Seen by Telstra (AS1221)

1

1.02

1.04

1.06

1.08

1.1

1.12

1.14

Nov-99

Dec-99

Jan-0

0

Feb-0

0

Mar -

00

Apr -00

May-00

Jun-0

0

Jul-0

0

Aug-00

Sep-00

Oct-0

0

Nov-00

Dec-00

Jan-0

1

Feb-0

1

Billi

ons

Raw Data

Adjusted

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0.0

0.5

1.0

1.5

2.0

2.5

Nov-99

Dec-99

Jan-0

0

Feb-0

0

Mar

-00

Apr-00

May

-00

Jun-0

0

Jul-0

0

Aug-00

Sep-00

Oct-0

0

Nov-00

Dec-00

Jan-0

1

Feb-0

1

Mar

-01

Ad

dre

ss

es

(M

illio

ns

)

Allocated

AS 1221, adjusted

Named Addresses

Addresses in Use

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y = 0.1626x - 140.06

R2 = 0.9688

54

54.5

55

55.5

56

56.5

57

57.5

58

% o

f A

lloc

ate

d A

dd

res

se

sRouting Table Address Growth

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McFadden/Holmes/Mylotte ProjectionPurported Worst Case, Most Likely and Best Cases

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Rate of Depletion• Annual growth rate

– McFadden/Holmes assumes low/medium/high growth of 30%/50%/80% respectively.

– RIR data shows annual growth of about 3%, with a negative second derivative

– Geoff Huston’s data shows annual growth of roughly 7%

• Order of magnitude discrepancy!• The trend does NOT appear to be exponential overall.

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Marketing Analysis

• Numerous statistics, no attribution• No traceability of assumptions• No verifiability of source data

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Lessons

• The RIR team will continue to focus on conservative analysis and extrapolation of verifiable quantitative data.

• Debate is a healthy thing - “Let a thousand flowers bloom.”

• We will make RIR source data available to independent researchers.

• Policymakers in the RIRs, ASO, IETF and elsewhere should benefit from diverse inputs and should reach their own conclusions.

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Acknowledgments

• Frank Solensky, Gotham Networks• kc claffy, CAIDA• Geoff Huston, Telstra• Cathy Murphy, ARIN• Paul Wilson, APNIC• Axel Pawlik and Mirjam Kuehne, RIPE NCC• Tony Bates and Phillip Smith, Cisco• Mark Kosters, Verisign• Christian Huitema, Microsoft