IT Dojo: Answers to five questions about IPv6

Bill Detwiler: The switch from Internet Protocol version four to Internet Protocol version six is a hot topic on TechRepublic.

If you're still unsure what this change really means, and you don't know what you should do to prepare for it, stay tuned. I'm Bill Detwiler, and during this IT Dojo video, I'll answer some of your most basic questions about IPv6.

Since TechRepublic members had lots of questions about IPv6, Michael Kassner, one of our Network Administrator bloggers, interviewed experts at both ARIN -- the American Registry for Internet Numbers -- and Command Information, a private company which provides Internet services.

We've used the material from those interviews for this video. At the end of the video and from within the IT Dojo blog, I'll provide a link to the Michael's complete series on IPv6.

Now, I suppose we should start by examining the main difference between IPv4 and IPv6.

Briefly, Internet Protocol is a set of technical rules that define how computers communicate over a network.

Deployed in 1981, IPv4 was the first version to be widely used and accounts for most of today s Internet traffic. IPv4 uses 32-bit addresses in a dot-decimal notation. With this addressing scheme, IPv4 provides just over 4 billion addresses. That number sounds like a lot, but it won't last forever.

First deployed in 1999, but not yet widely adopted, IPv6 is a newer numbering system designed to replace IPv4. The major difference between the two standards is the number of IP addresses that each allows.

IPv6 uses 128-bit addresses and Hexadecimal notation. It provides more than 16 billion-billion addresses. Most experts believe this number of addresses will last up for a while.

Now there are a few other differences, like mandatory network layer security, but it's the dramatic increase in available addresses that is most significant.

The second question many TechRepublic members asked is what does it mean for the two protocols to coexist?

The technical functioning of the Internet remains the same in both versions and it is likely that both versions will continue to operate simultaneously on networks well into the future. To date, most networks that use IPv6 support both IPv4 and IPv6 addresses in their networks.

While it's important for all organizations to consider the adoption of IPv6 for their Internet services over the next couple of years, you should know that IPv4 is not going away. Although it is necessary to make certain services like Web sites and e-mail available over the IPv6 network, it is not necessary to replace the already deployed IPv4 infrastructure.

The bottom line is that the complete transition will happen over the course of many years, with both protocols working together on the Internet.

Another area of concern from many TechRepublic members is hardware and software compatibility. Many members asked if older desktops could support IPv6, and specifically, which versions of Windows support IPv6?

While some level of support (although not necessarily through Microsoft)is available for older Windows systems -- even back to 95 and NT -- it's important to note that Windows XP, Vista, and Mobile all ship capable of running IPv6. Vista and Windows Mobile default to having IPv6 turned on, but the user has to turn it on in XP.

Because the world of devices is so vast, you will have to check with your individual vendors for details.

Number four, what about having IPv6 perimeter IP addresses and IPv4 IP addresses on the internal network?

According to ARIN, organizations should consider  dual-stacking  IPv4 and IPv6 so they can continue to communicate with IPv4 portions of the Internet, yet be able to communicate with the new and soon-to-expand IPv6 portions. ARIN advises organizations to begin by deciding what to do to make their routers, DNS, Web servers, and mail servers compatible with IPv6.

The level of effort to make Web site, e-mail, and other communication services available via IPv6 will be different for each organization. For example, some business entities host and manage their own Web sites and e-mail services.

These companies will need to update the public-facing portion of their networks and servers so they are dual-stacked. This involves work at their own facility and coordinating with their service provider(s) to ensure some form of IPv6 connectivity is available.

Finally, members asked us how IPv6 addressing actually works and to explain the IPv6 shorthand.

Command Information explained this one for us. An IPv6 address is made up of eight 4-character hexadecimal chunks, each separated by a colon. For example: 2001:0db8:0049:0000:ab00:0000:0000:0102

is a full IPv6 address.

The first four chunks (or 64 bits) of the address identify the network portion of the address, referred to as the  network prefix. 

Because IPv6 addresses are hierarchical, the network prefix identifies the organization, service provider, and other elements of distribution. The last four chunks (64 bits) compose the interface ID, a unique identifier that is often created using a device s MAC address.

Because a full address like this one can be cumbersome, addresses can be compressed via two easy steps.

First, all leading zeros within a given chunk can be eliminated. For this address, it would reduce to 2001:db8:49:0:ab00:0:0:102. Additionally, once per address (and only once; otherwise, you'd risk ambiguous addresses), any number of consecutive, all-zero chunks can be replaced by a double colon, making the most compressed form of the above address, which looks like: 2001:db8:49:0:ab00::102.

These are only some of the great questions about IPv6 submitted by TechRepublic members and answered by the experts. For more details, see Michael Kassner's full series of articles and interviews on this topic, which I'll like to from the IT Dojo blog, and let us know in the IT Dojo blog if there are other upcoming technology issues that you want to know more about.

And as always, for more teachings on your path to becoming an IT Ninja, visit itdojo.techrepublic.com. And please let us know if this tip was helpful.

You can also submit your favorite IT Ninja tips by e-mailing them to us at itdojo@techrepublic.com. If we use them for an episode of IT Dojo, we'll send you a TechRepublic coffee mug.

I'm Bill Detwiler. Thanks for visiting TechRepublic's IT Dojo.