BGP’01

An Examination of the Internet’s BGP Table Behaviour in 2001

Geoff HustonTelstra

The Predictions

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Worst CaseContinued Exponential Growth150,000 entries by January 2002

Best CaseElimination of all extraneous routing entries75,000 entries by January 2002

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What Happened

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BGP in 2001 Growth in Internet table size contained at

roughly 105,000 entries through the year

Is this a stable state? For how long? Will exponential growth resume? When?

Why? Did the Internet stop growing in

size? Or are we doing a better job at

managing the impacts in the routing space?

Or is there some other factor at work?

2001 - Route Views’ View

Wide variation between largest and smallest AS (27%)

Main Cluster of AS’s

2001 – Main Cluster Behaviour

2001 – 5 “Phases” January – June

Continued growth in number of prefixes Mid June

3 week decline in number of entries Late August

2 week decline Late November

1 week sharp decline December

Resumption of growth

Has the Internet Stopped Growing in 2001? A number of other metrics do not

show the same pattern as the number of BGP table entries: Total routed address space Number of AS’s Number of “root” prefixes in the BGP

table

Internet Size:Routed Address Space

Address Space Total routed address space grew by an

annual rate of some 8% Steady growth in total routed address

space, modulo /8 advertisement changes Interestingly, not all AS’s reach all

routed address space Some balkanization is evident Not clear whether this is a result of

aggressive prefix length filtering or deliberate outcomes from routing policy settings