You are probably already aware that the global implementation of IP is version 4. When IPv4 was developed it was more than what was needed for the 1970s networking world. But it wasn’t designed to handle what we have been throwing at it: millions of worldwide connected computers transporting data around the clock.
Because IPv4 was designed with 4-octet addressing (which handles only about 4.3 billion addresses), the number of addresses we can use is limited. Network Address Translation (NAT) has helped to ease the strain on the addressing problem, but IPv6 can support about 50 octillion IP addresses. That should keep us set for a while.
But IPv6 is more than a way to extend addressing schemes. True, it does provide a 128-bit address space. In addition, IPv6 streamlines header and addressing to support hierarchical routing infrastructures (making IPv6 routers faster). Security is also beefed up with IPv6 by enhancing protection against scanning attacks and requiring the use of the Internet Protocol Security (IPSec) for cryptographic protection of your traffic. You can learn a lot more about these and other features from “The Cable Guy” (a series of articles written by Joseph Davies, a technical writer in the Windows Networking and Device Technologies Group at Microsoft). For the purposes of this discussion, the article you should read is at http://www.microsoft.com/technet/community/columns/cableguy/cg1005.mspx. In addition, you can read the book Understanding IPv6 by Joseph Davies, which can help you to start planning to transition to IPv6 internetworking and find out all about the next-generation Internet—from its features and benefits to its packet structure and protocol processes.
Bradley Mitchell, an industry professional specializing in networking software with a bachelor’s degree from M.I.T., commented on IPv6 and Vista.
The new Microsoft Vista operating system contains built-in support for the IPv6 network protocol. Some news outlets recently have suggested Vista IPv6 may cause Internet network traffic problems. It’s true that some extra traffic to DNS servers will be needed to support IPv6 queries, but this by itself is no big deal. In the long run, IPv6 will become the standard for Internet Protocol support, which will help the Net continue to grow for many years to come.
IPv6 wasn’t released with Vista; it has actually been included in earlier OS versions (Server 2003 and Windows XP had support for IPv6). The capabilities offered were limited and configuring the settings required using the command-line tools, but it did exist. So, how is the Vista version different? In the article “How Vista Will Handle IPv6” on http://www.windowsdevcenter.com, Mitch Tulloch gave an excellent overview of the differences.
The key difference between the old and new platforms is that prior to Vista the TCP/IP networking stack of all Windows platforms was implemented as a dual-stack architecture. This meant that the driver for the IPv6 stack (Tcipi6.sys) was a separate networking component from the driver for the IPv4 stack (Tcpip.sys), so if you wanted IPv6 connectivity you had to install IPv6 protocol support from the Network Connections folder because in Windows XP and Windows Server 2003 only IPv4 is installed by default. It also meant that the IPv4 and IPv6 stacks each had their own separate transport layer so they implemented TCP and UDP separately. Additionally, each stack had its own separate framing layer to encapsulate IPv4 and IPv6 packets for transmission over different LAN or WAN media.
In Vista (and Longhorn Server), however, a fundamental change has taken place, for the Next Generation TCP/IP stack is now implemented as a dual-layer architecture, not dual-stack. That means the two network layer components for IPv4 and IPv6 share the same transport layer components for TCP and UDP. It also means that IPv4 and IPv6 share a common framing layer at the bottom of the stack. And it means that IPv4 and IPv6 are both enabled by default—there’s no separate protocol to install using the Network Connections folder—though it is possible to disable IPv6 support at the physical layer in Vista if you’re in an all-IPv4 networking environment. But the idea is that we’re not likely to remain in such pure IPv4 environments for long as more and more large enterprises (and possibly whole countries like China, Japan, and South Korea) migrate their legacy IPv4 networks to IPv6, so leaving IPv6 enabled by default is probably a good idea.
In Vista now you also can configure IPv6 settings using the GUI and not just using netsh from the command line. Another change is that Teredo, an IPv4/v6 transition technology for supporting end-to-end communications through NATs using IPv6 global addresses, is enabled by default on Vista computers that are members of a domain. Still another enhancement in Vista is that IPSec over IPv6 now fully supports both data encryption and IKE, and instead of having to configure IPSec policies and security associations from the command line, now you can use the IPSec snap-in to do this more easily from the GUI. Finally, the new APIs of the Next Generation TCP/IP stack let developers write network-aware applications more easily, though consideration should be given to ensuring that applications are still compatible with down-level Windows platforms.
To learn more about IPv6, you can read the RFC posted on the Internet Engineering Task Force website at http://tools.ietf.org/html/rfc2460.
IPv6 and Ad-Hoc Networking
Microsoft has enabled IPv6 by default in Vista. There are several reason for this change, and instead of complaining about it, we should just get on board. Why? Well, let’s consider the words of Brien M. Posey (www.brienposey.com), a technical author who has produced thousands of articles, tips, and whitepapers since 1995. He wrote an article called “Get Ready to Run IPv6 (Whether You Want to or Not),” which was originally posted on Windows Networking.com. You can also find it at http://searchnetworking.techtarget.com/home/0,289692,sid7,00.html, though. Here are some of the highlights:
The United States federal government has mandated that all federal agencies must make the transition to IPv6 by June of 2008. In an effort to make the transition easier for the government and for others, Microsoft has enabled IPv6 by default in Windows Vista. Since most people expect IPv6 to be the protocol of the future, Microsoft has based at least some of Vista’s new networking features on this protocol.
When Microsoft created Vista’s peer networking component, one of their goals was to make it easy for anyone to transition between corporate networks and ad-hoc networks. As such, the development team worked under the assumption that people other than IT professionals would want to use the peer networking feature and that external resources such as DNS servers and DHCP servers would not be available.
This is where IPv6 comes into play. IPv6 supports discovery of services in a way that makes ad-hoc collaboration possible. For example, let’s assume that a group of people wants to form an ad-hoc network and communicate using the collaboration services. As the network is formed, one person in the group launches an application that is designed to integrate with the collaboration services. As soon as the collaboration services start, they transmit a multicast message to everyone on the ad-hoc network notifying them of the service’s availability.
Obviously, there is a lot more to learn about IPv6 and over the coming months and years we will certainly see more information released by Microsoft on how IPv6 will be implemented in future products.
