How one university is switching to IPv6 on its own terms

Central Michigan University is beginning its transition to the next generation of Internet Protocols while it still has plenty of IPv4 addresses left, giving network administrators plenty of time to listen, learn and then implement IPv6 on its network.

“We know IPv6 is coming,” said the university’s network manager, Ryan Laus. It is being driven largely by the exhaustion of new addresses available under the original protocols.

But starting the transition now rather than waiting for the transition to be forced on it by demand gives the school located squarely in the middle of the state’s Lower Peninsula, whose main campus is in Mount Pleasant, a chance to move at its own pace.

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The Internet Protocols are the set of rules and specifications enabling communication and interoperability among components on the Internet and other IP networks. Version 4 of the protocols is commonly in use today. Its addressing scheme has a limited number of unique addresses which now is nearing depletion. This means that future growth on the Internet increasingly will require the use of IPv6, which has a much larger address space.

The two versions are not interoperable, however, and adoption of the new protocols has been limited. In an effort to spur the inevitable transition, the Internet Society is following up last year’s World IPv6 Day test flight with global launch on June 6 when major service providers, equipment vendors and websites will permanently enable the new protocols on their networks, hardware and sites.

 Laus said that although CMU is making a start, it will not have IPv6 up and running by launch day.

“We’re moving at a slow pace,” he said. “We are rolling out a dual-stack network,” capable of handling both IPv4 and IPv6 traffic. “We’d like to hit the low-hanging fruit first, such as the main Web server — the easy things. We’re hoping to have the low-hanging fruit done by this fall.”

The initial phase is expected to take years, he said. “Three years from now, we will probably have dual stacks in all locations. Then we might selectively start turning IPv4 off in some locations.”

The need to begin planning for the transition to IPv6 became apparent with the change several years ago in students’ online habits.

“About three years ago, we experienced a huge growth in the number of wireless devices,” Laus said, and the number of wireless users now dwarfs the roughly 14,000 wired addresses on the campus network. When classes are in session, about 26,000 unique wireless devices touch the network each day. “That number will only go up.”

The campus has 36,000 wired network ports, but many of them are in residence halls where they go unused in favor of wireless connections. Four years ago, most students still brought desktop PCs to school with them that used the wireline connections. Today they bring laptops, almost all of them wireless.

“It makes me sad as a network administrator to see those connections go unused,” Laus said. But the writing is on the wall: Wireless connectivity now drives network development, and administrators are expecting large increases in demand as the number of mobile devices increases.

For the time being, that demand can be met with IPv4. The school started with a /16 block of about 64,000 addresses from its service provider, Merit Network, a member-owned nonprofit formed in 1966 to link the state’s public universities. To accommodate the influx of wireless devices, it obtained a second /16 block.

“We figured that would hold us for the next few years while we transitioned,” Laus said.

In preparation for the transition, the school also obtained a /32 block of IPv6 addresses, which dwarfs the available supply of IPv4 numbers. “It’s an ungodly number,” Laus said. “It has a lot of commas.”

The question remained of when to make the transition. “So far we haven’t seen that huge a demand” for the new addresses, but the decision was made to start the process now so it could be done “on our own terms.” This will give the administrators time to get the training and experience needed to manage the new protocols and to understand how their networking tools and applications handle them.

“There are behavioral differences with IPv6,” he said. “Dual-stacking will allow us to judge performance before getting hit with a flood.”

Almost all networking equipment today will nominally support IPv6 traffic. But there is little real-world experience so far for how well it is handled. Many industry observers feel that the current capacity for handling IPv6 is “good enough,” at least for the initial demands that will be made by the new protocols.

“I feel that there is a reasonable expectation,” said Chris Smithee, network security manager for Lancope, which supplies network monitoring tools. “Will there be some hiccups when we see large-scale adoption? Yes.” But he added that after four decades of experience, managing IPv4 remains an inexact science. “We are never really going to understand everything.”

Much of the real-world experience with IPv6 today is coming from Asia, where IPv4 addresses were never as plentiful as in North America and where adoption of the new protocols has been more aggressive. Laus said he wants to take advantage of any experience he can to help his own transition. He is looking to his ISP, Merit Network, for some help and said he wants to take as many formal courses as possible, such as IPv6 security courses offered by the SANS Institute.

So far, he says, there is little help available from his peers, who typically are no further along in the transition than he is. “For the most part, they still have IPv4 on their networks,” he said.

Although Laus said he could envision beginning to turn off IPv4 in some parts of the network within three to five years, the current protocols are not likely to disappear anytime soon. A wholesale transition of users to new addresses could be disruptive, meaning that legacy IPv4 addresses will be accommodated for the foreseeable future. And although networking equipment can handle IPv6, some older peripheral networked hardware does not and will have to be replaced before the shut-off occurs.

Some of the equipment such as printers probably will be updated on relatively short time frames. But some limited-use tools such as time clocks are liable to be in place for a long time, meaning IPv4 probably will be around with them.


About the Author

William Jackson is a Maryland-based freelance writer.

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