Don’t Blame the Market for Breaking the IPv4 Routing Table

There are many misconceptions about the IPv4 market.  Often, these misconceptions are red herrings, repeated in different venues to transform them into conventional wisdom.

Market-driven block fragmentation blowing up the BGP routing table is one of those recurring red herrings.

The argument goes like this: sellers are chopping up their existing contiguous address space into multiple smaller blocks to sell the unused space to the highest bidders (which, on a per unit basis, favors small blocks). The resulting subdivision of previously contiguous address space introduces many new routes into the IPv4 routing system. This will in turn cause routing table size growth, and continued growth of the BGP table will lead (in the near future) to mass Internet-wide outages.   Therefore, the IPv4 market is bad for the Internet.

In reality, the BGP routing table is growing because the number of end points on the Internet is growing -- not because the IPv4 market is fragmenting blocks.  There is no evidence that block fragmentation from the IPv4 market is having any material impact on BGP routing table size.  More importantly, BGP is scaling to meet routing system growth– largely because the current generation of routers have more than enough processing capacity. Reasonably foreseeable increase in the IPv4 routing table size is no reason to panic. In his blog, Geoff Huston periodically examines BGP issues with data and keen insights. See, e.g.,

Of course, the IPv4 market does not obviate the need to migrate to IPv6, and IPv6 is the future of the Internet.  However, ARIN free pool depletion doesn’t mean the end of IPv4, nor does it mean that network operators must immediately abandon their IPv4 infrastructure investments.

The IPv4 market allows current network operators to reclaim old unused IPv4 numbers, and then put those unused IPv4 numbers back into productive use to support the growth of the Internet.  Moreover, transition to IPv6 is a costly and potentially complex endeavor, which must be planned responsibly (weighing all of the costs and benefits).   The market provides (and will for next several years) a post-RIR free pool means for network operators to obtain the IPv4 addresses they need while they execute their migration to IPv6.