David Conrad <drc@virtualized.org> writes:
Growth in IPv4 accessible hosts will stop or become significantly more expensive or both in about 2.5 years (+/- 6 months).
Growth stopping is extremely unlikely. Growth becoming significantly more expensive is guaranteed. ...
more expensive for whom, though? if someone has to find existing address space and transfer it at some payment to the current holder in order to grow their own network, that's a direct expense. if this became common and resulted in significant deaggregation, then everybody else attached in some way to the "global routing table" would also have to pay some costs, which would be indirect expenses. unless a market in routing slots appears, there's no way for the direct beneficiaries of deaggregation to underwrite the indirect costs of same. at a systemic level, i'd characterize the cost of that kind of growth as instability rather merely expense.
Address utilization efficiency will increase as people see the value in public IPv4 addresses. ISPs interested in continuing to grow will do what it takes to obtain IPv4 addresses and folks with allocated- but- unused addresses will be happy to oblige (particularly when they accept that they only need a couple of public IP addresses for their entire network). At some point, it may be that the cost of obtaining IPv4 will outstrip the cost of migrating to IPv6. If we're lucky.
the cost:benefit of using ipv6 depends on what other people have deployed. that is, when most of the people that an operator and their customers want to talk to are already running ipv6, then the cost:benefit will be compelling compared to any form of continued use of ipv4. arguments about the nature and location of that tipping point amount to reading tea leaves. nevertheless if everybody who can deploy dual-stack does so, we'll reach that tipping point sooner and it'll be less spectacular. -- Paul Vixie Chairman, ARIN BoT