John Curran has a message for ISPs: Don't expect to be bailed out if you haven't already started the upgrade to IPv6.
Curran, CEO at the American Registry for Internet Numbers, told an audience at this week's FutureNet conference that the next 18 months will represent a "Judgement Day" for ISPs that still think they can get by through improving the efficiency of their IPv4 address use. The bottom line, Curran said, is that there simply won't be anymore IPv4 addresses in a year and a half.
"We will start turning down requests for IPv4 addresses," Curran said. "There won't be any. The reality is we're going to run out."
IPv6 is a next-generation Internet layer protocol that was designed by the Internet Engineering Task Force (IETF) to solve the problem of IP address depletion under the current Internet layer protocol, IPv4. While IPv4 has a fixed limit of around 4 billion IP addresses, IPv6 will have exponentially more, on the magnitude of around 340 billion billion billion billion (3.4×1038).
The trouble that IPv6 advocates and ISPs have run into so far, however, is that many of the ISPs' enterprise customers don't see the logic in investing time and money in IPv6 deployment during a recession where they have far more pressing and immediate needs.
Additionally, Curran said that merely switching to IPv6 isn't going to be a clean transition since IPv6 is not backward compatible with IPv4. Therefore, ISPs will have to support both protocols for the foreseeable future, as IPv6 addresses typically connect to each other over IPv4 networks through encapsulating IPv6 data in IPv4 packets and then "tunneling" through the older network. In other words, there's no simply way to flip a switch and have every network upgrade to IPv6 without keeping IPv4 around.
"There's going to have to be two networks, there's no clean way for us to solve that problem," he said. "For potentially decades we'll have to run IPv4 parallel to IPv6."
From a practical standpoint, Curran recommended that ISPs begin preparing their customers for the transition to IPv6 immediately by offering to connect them through both IPv4 and IPv6. He noted that while demand for IPv6 might not be all that strong now, it will grow much more rapidly once ARIN runs out of IPv4 addresses over the next 18 months.
"Demand for IPv6 support will become mandatory very, very quickly," he said. "Introduce IPv6 support into your product cycle as soon as possible."
If all of this sounds like a chaotic and piecemeal process, Curran said to take heart from the fact that ISPs are highly unlikely to ever make a similarly jarring transition for a very long time.
"The good news is that we don't expect to leave IPv6," he said. "It will be several centuries before we have to worry about it no matter how crazy we are."