Why have 32-bit ASNs been introduced?
With 16-bit AS Numbers, around 65,000 unique numbers are possible. Around 73% of these numbers have already been assigned. Studies have shown that with the present assignment rate, the supply of 16-bit ASNs will be exhausted between 2010 and 2015. The introduction of 32-bit ASNs increases the supply of AS Numbers to four billion.
