Experts warn of tough times ahead for transition to IPv6

Saint Augustine may not be the patron saint of networking, but his fabled words ring true about many people in the industry as it inches reluctantly towards the biggest transition since the launch of the World Wide Web: "Lord please make me good, but not yet."

Everyone knows that IP addresses are fast running out and that the only long-term solution is a move from IPv4 to the virtually limitless address space of IPv6.

But pity the poor IT executive who has to try to persuade his bosses to finance a change that promises a lot of hassle, including possible business disruptions, for something of no immediate benefit that nobody except geeks are going to notice.

There is a lot of procrastination going on. Karl Penalula, president of BT's 21st Century Network, told the IPv6 World Forum in London this week that half of his enterprise customers had no IPv6 plans in place.

Making matters worse, paradoxically, is the fact that, with workrounds, there is no shortage of IPv4 addresses.

Alain Durrand, director of software engineering at Juniper Networks, pointed out that the number could be increased a thousandfold by the use of network address translation (NAT), hiding a large address space behind a single number.

"The trouble is that, if we do that, we increase the complexity. And the root cause of most problems for operators is the complexity of the network," said Durrand, who co-chairs an Internet Engineering Task Force group specifying standards for carrying IPv4 traffic across IPv6 networks and vice versa.

Large NATs also represent a security problem because they can make it impossible to trace the source of malicious attacks and other criminal activity.

According to Jason Fesler, senior principal architect at Yahoo, they also threaten location-based services such as targeted advertising because one address may cover many machines many miles apart.

NATs, and the fact that addresses can be recycled by scrapping legacy equipment, mean that there will be no address crisis in Europe for at least a couple of years, giving companies and government organisations an excuse to put off decisions at a time when money is tight.

Listening to delegates at the IPv6 Forum you could be forgiven for wondering whether IPv6 will ever get off the ground.

They reported that last week's IPv6 day went off with barely a hitch, with IPv6 traffic soaring, albeit from a relatively small base.

However, Niall Murphy, an IPv6 engineer with Google Ireland, said that it revealed a persistent level of "brokenness", in other words links that failed because equipment did not properly support IPv6.