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IPv6: Time to Get Started
By Andy Rosenzweig
We are quickly approaching the moment when networks and services must be made compatible with IPv6. A long-foreseen issue that threatens the smooth functioning of the Internet, IPv4 depletion is now a defined challenge for organizations and network engineers to begin dealing with.
While specific actions vary depending on individual circumstances, the general issues are well understood and organizations can begin work now to prepare themselves for the future. There is currently a rare luxury to take some time to gracefully learn and prepare for implementing IPv6, but the duration of this period is unknown and it will surely pass quickly. IPv6 is an inevitability, and the time to begin work is now.
The problem: IPv4 is (too) finite
For many years it has been well understood that the pool of available IPv4 Internet addresses will one day become depleted. Although IPv4's 32-bit addressing scheme (in the familiar form nnn.nnn.nnn.nnn) provides about 4.3 billion addresses, the popularity of the Internet and ubiquity of network-connected devices means that even this large supply is not adequate for future needs.
The predicted depletion took a giant step toward reality in February 2011, when it was announced that all remaining unallocated IPv4 address blocks had been assigned by The Internet Assigned Numbers Authority (IANA)—the worldwide IP address registry--to the five regional registries that in turn distribute addresses to network operators. This event means that there are no more addresses left to be distributed from the finite global supply, and relatively few addresses remain with each of the regional registries. There will come a time—sooner in some parts of the world than in others--when network operators will not be able to apply for and receive new addresses.
The implications of depletion are sobering. Running out of addresses (absent another solution) would mean that service providers and network operators could not readily expand access. ISPs could not add customers, web sites could not add servers, and organizations could not add computers for new employees or users. The Internet, still expanding at a rapid pace, would hit wall and growth would be slowed or stopped by the lack of a very basic element.
The solution: IPv6
With an eye toward this eventual depletion, standards organizations over a decade ago finalized the IPv6 standard, whose primary feature is a much larger supply of addresses. IPv6 provides a 128-bit addressing scheme, allowing for about 3.4x10^38 unique addresses--an immense number that is expected to meet all needs for a very long time.
Much of the infrastructure for using IPv6 is in place. IPv6 addresses can be acquired for use on individual networks. Most network-ready devices on the market today are IPv6-capable, meaning that they can be assigned an IPv6 address and communicate with other IPv6-addressed devices. And most software products with network components are likewise prepped to be IPv6-friendly.
Problematically, though, IPv6 is not directly compatible with IPv4. A device that only has an IPv4 address cannot communicate directly with a device that only has an IPv6 address, and vice versa. To communicate, both devices must have IPv6 addresses, and be connected along a network path with routers and switches that can likewise pass IPv6 traffic. But today, and for the long period it will take to completely transition to IPv6, devices attached to the Internet essentially need to be able to communicate using both IPv4 and IPv6. That means in order to be fully functional, each device needs both an IPv4 and an IPv6 address—or be served by one of several transitional technologies that allow address translation from IPv4 to IPv6.
Organizations that operate networks and provide information via the Internet essentially need to resolve two scenarios in order to be fully ready for IPv6:
- Serve incoming IPv6 traffic. For example, an organization's web servers should be able to communicate with external computers that are sending requests only via IPv6. This accommodates the eventual reality that network operators somewhere in the world will provide their users only with IPv6 service, without a user-side IPv6-to-IPv4 translation service.
- Serve outgoing IPv6 traffic. This will ensure that computers on the organization's own networks can reach services that are available only via IPv6. Few such scenarios exist today, but they are entirely possible and it is unpredictable when they will become more prevalent.
Resolving both scenarios involves considering the specifics of the network architecture, implementing IPv6 on all network routing devices, and determining the best course for providing address translation. There are several options, which are beyond the scope of this article, and that require independent evaluation for each network scenario.
What to do now?
Regardless of ultimate solutions, organizations can take a number of foundational steps now to ensure readiness for their transition to an IPv6 Internet.
An early step should be to acquire a block of IPv6 addresses for experimentation and testing. Merit has a large allocation of IPv6 addresses and can assign blocks to any Merit Member. Engineers and technicians can then set up their own internal test networks and devices to begin learning about supporting IPv6. It is important that network staff become well trained in IPv6 theory and practice.
Another valuable step is to inventory critical systems to ensure that they are IPv6-ready. Specifications for routers, switches, computers, printers, wireless access points and other devices should be researched to learn which are and which are not IPv6-addressable. Those that are not should be noted for eventual replacement.
Organizations should likewise ensure that specifications for devices and software to be purchased in the future should specifically require IPv6 compatibility. Compatibility of new devices should be tested soon after purchase.
With some of those basics covered, attention can then be paid to specific solutions for supporting IPv6. Most experts agree that attention should be paid first to ensuring that information services such as web servers are accessible by IPv6—the "incoming" scenario . This guards against occasions--sure to become reality in the future—where a computer somewhere in the world can only communicate via IPv6. Preparing for this scenario ensures that people seeking information from your organization are not blocked by technology.
When will this become a problem?
We are in the early stages of a transitional period that will take an unknown amount of time—certainly years. For the immediate moment, it's possible to say that there is not a crisis; we have not experienced a situation where IPv4 addresses are unavailable and it has been impossible for service providers to provide a bridging technology.
But it is unquestionable that a global transition is in process, and IPv6 will without a doubt ultimately be ubiquitously implemented throughout the Internet. Whether the transition takes two years or ten, there is a clear need and responsibility to prepare and to become fully informed. The current moment, when IPv6 implementation is inevitable yet not at a crisis point, is the right time to act.
Resources
The March 2011 issue of The Internet Protocol Journal focused on IPv4 exhaustion and the transition to IPv6. A number of excellent articles step through the important factors in clear language.
http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_14-1/index.html
In August, 2011, Merit hosted a webinar featuring John Curran, president and CEO of the American Registry for Internet Numbers (ARIN), the Internet address registry for North America. Curran's presentation, "Ready or Not...IPv6 is Here" can be viewed at:
http://www.merit.edu/events/archive/specialevents/webinarseries/20110811_archive.php
At the September 27, 2011 MJTS meeting, Allen Kluender from Cisco addressed some of the aspects of preparing information services for IPv6, in a presentation titled "IPv6-Enabling Your Web Presence". That presentation can be viewed at:
http://www.merit.edu/events/mjts/agenda.php?mjtsdate=20110927
To request a block of IPv6 addresses, Merit Member organizations may contact their Member Relations Manager. The Merit backbone network is fully IPv6 capable, and ready to support traffic between Member sites.
January 2012 - Merit Connections Newsletter
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