The day IPv4 addresses run out is happening any day now, with the North American registrar now down to 0.01% worth of /8 address space available. However, thanks to more rigid rationing, the Asia-Pacific region still delayed its exhaustion somewhat. But with plenty of unused address space still left in North America on the commercial transfer market, depletion for now does not mean the end of the world, but rather much higher prices for new projects and an added impetus for moving to IPv6 where possible.
Paul Wilson, director-general of APNIC, the Asia-Pacific Network Information Center, spoke to TelecomAsia of the challenges of transitioning to IPv6 explaining that while telecom executives like to think that it is simply the matter of flicking a switch, behind that switch there are untold numbers of engineers pulling their hair out trying to please their bosses and get everything to work together.
IPv6 transition is non-trivial and potentially expensive.
“If it is as simple as turning it on, why haven’t you turned it on already? Then if not, when actually are you going to flick this mythical switch? If someone says it’s easy their either optimistic or ignorant,” he said.
The ideal model for telcos and ISPs to adopt is a dual-stack approach, that is the operation of both v4 and v6 throughout a given component and ideally that would mean dual-stack use of both address sets within the entire infrastructure.
That would make it the simplest way as the telco would not have to deal with mapping or translation and makes for a more simple DNS configuration.
The only reason that some operators might be opting for something else rather than dual-stack would be that some component of network is v4 or v6 only.
Some phone networks have gone for v6 only and they require address mapping for their v6 handsets. The reason is that some [older] phones’ capabilities are limited and it’s easier for them to run a single protocol stack.
LTE handsets can mostly run dual-stack but older handsets may mean that a single protocol stack is easier.
Another reason is that in 3G, running v4 and v6 together requires a double circuit.
It all boils down to very specific deployment scenarios.