of debate and analysis with the design of a new, extended address format called IPv6. (IPv5 was an experiment in stream applications that did not scale and was abandoned.) IPv6 had a small number of new features and a format intended to expedite processing, but its principal advantage was 128 bits each of source and destination host addresses. This is enough for 340 trillion trillion trillion addresses—enough to last for the foreseeable future.

The IPv6 format is not backwards compatible with IPv4 since an IPv4- only host does not have the 128 bits of address space needed to refer to an IPv6-only destination. It is therefore necessary to implement a dual-stack design that allows hosts to speak to either protocol for the period that both are in use. Eventually, address space will not be available for additional IPv4 hosts, and IPv6-only hosts will become necessary. Hopefully, ISPs will be able to implement IPv6 support before the actual exhaustion of IPv4 addresses, but it will be necessary to allow for dual-mode operation for some years to come.

World IPv6 Day is scheduled for June 8, 2011, at which time as many ISPs as are willing and able will turn on their IPv6 support to allow end users and servers to test the new protocol on a global scale for a day. The move to IPv6 is one of the most significant changes to the Internet architecture since it was standardized in the late 1970s and early 1980s. It will take dedicated effort by many to ensure that users, servers, and Internet service and access providers are properly equipped to manage concurrent operation of the old and new protocols.

Here, Thomas Limoncelli considers steps that can be taken to achieve this objective.

strategies of organizations that are making the transition. The strategies that work tend to be those that focus on specific applications or Web sites rather than trying to convert an entire organization.

The biggest decision for many organizations is simply knowing where to begin. In this article, I consider three possible strategies.

The first scenario we present is a cautionary tale against what might be your first instinct. Though fictional, we’ve seen this story played out in various forms. The other two examples have proven to be more successful approaches. Knowing this, we would offer the following advice to a business contemplating the transition to IPv6: start with a small, well-defined project that has obvious value to the business.

someday the u.s.
will run out
of three-digit
telephone area
codes and
will be forced
to add a digit. as
Vint Cerf explained,
the internet is facing
a similar situation.

—Vinton G. Cerf

 

strategies for moving to iPv6 Someday the U.S. will run out of three-digit telephone area codes and will be forced to add a digit. As Vint Cerf explained, the Internet is facing a similar situation with its address structure. Often predicted and long ignored, the problem is now real. We have run out of 32-bit IP addresses (IPv4) and are moving to the 128-bit address format of IPv6. This section looks at some

story 1: “upgrade everything!”

While having a grand plan of upgrading everything is noble and well intentioned, it is a mistake to think this is a good first experiment. There is rarely any obvious value to it (annoys management), it is potentially biting off more than you can chew (annoys you), and mistakes affect people that you have to see in the cafeteria every day (annoys coworkers).

This strategy usually happens something like this: someone runs into the boss’s office and says, “Help! Help! We have to convert everything to IPv6.” This means converting the network equipment, Domain Name System (DNS), Dynamic Host Configuration Protocol (DHCP) system, applications, clients, desktops, servers. It’s a huge project that will touch every device on the network.

These people sound like Chicken Little claiming the sky is falling.

These people are thrown out of the boss’s office.

A better approach is to go to the
boss and say, “There’s one specific
thing I want to do with IPv6. Here’s
why it will help the company.”
These people sound focused and
determined. They usually get funding.

Little does the boss realize this “one specific thing” requires touching many dependencies. These include the network equipment, DNS, DHCP, and so on—yes, the same list of things