IPv6 Overview

The next IP standard is finally getting the support it deserves

Some product innovations are sudden responses to new technical capabilities. Other innovations are more gradual changes to support slowly evolving technologies. One such evolving technology is IP version 6 (IPv6). This revolution of the Internet Protocol has been in process for years—see "The Next Generation IP in Action," June 1998, http://www.winnetmag.com, InstantDoc ID 3478 for Windows & .NET Magazine's introductory piece about the standard—but is finally starting to have a noticeable effect on products. Most enterprises and ISPs likely will migrate to IPv6 within the next 5 years. IPv6 isn't backward-compatible with IPv4, so now is the time to discover how IPv6 will affect the products you use and which new products are building on this standard to meet the requirements of the future.


New Horizons

The Internet depends on IP addressing and routers, which provide the backbone for our networks. The current Internet address system—IPv4—uses a 32-bit value (e.g.,, which has worked well until now but is fast becoming inadequate as the demand for IP addresses continues to climb. Global adoption of the Internet is partially to blame; certain areas in Asia soon will run out of IP addresses. Another reason for the explosion in the assignment of IP addresses is the rapid growth of mobile devices. The emergence of embedded devices in everything from refrigerators to light switches is poised to further increase the need for IP addresses.


IPv6 replaces the current 32-bit value with a 128-bit value, increasing the size of an IP address by a factor of 4. This change increases the number of possible Internet addresses to 340,282,366,920,938,463,463,374,607,431,768,211,456. To put this number into perspective, the current system's 4.3 billion addresses aren't even one-billionth of 1 percent of the new address range.

Such an expansion of the IP address range isn't trivial, but IPv6 does more than just increase the number of available Internet addresses. The Internet Engineering Task Force (IETF) saw the need for a transition as an opportunity not just to expand the range of addresses but also to adjust key elements of the IP standard. The changes begin with a new IP request header format that supports several new capabilities in areas such as routing, network security, and network configuration. The new capabilities include an updated DHCP standard—DHCPv6—for dynamic assignment of IP addresses (aka stateful configuration), the use of a device's media access control (MAC) address within its IP address to dynamically create unique IP addresses at the router level (aka stateless configuration, which omits the DHCPv6 server), inherent hierarchy within networks, built-in support for IP security elements (including authentication, encryption, and integrity), the ability to dynamically discover the local router, and router advertisement (i.e., a router's active solicitation of potential clients).

These enhanced capabilities are changing products across several segments of the IT market. At its core, the IP layer is a low-level software implementation, but this implementation often takes the form of firmware that's burned into routers and other network devices. Therefore IPv6, which supports capabilities that weren't even envisioned when many of these products were designed and produced, affects everything from OSs to routers and firewalls. And because the switch to IPv6-capable software and hardware won't occur all at once, most organizations will need migration tools or services to help smooth the transition. Let's look at some of the changes happening in the software, migration, and hardware markets.


Software Support

All OSs, whether they come from major vendors (e.g., Apple Computer, IBM, Microsoft, Sun Microsystems) or niche companies, are gearing up to support IPv6. Microsoft officially supports IPv6 beginning in Windows Server 2003, Windows XP Service Pack 1 (SP1), and Windows CE 4.1. Microsoft doesn't provide IPv6 support for Windows 2000 or Windows NT, but you can access the unsupported tools that Microsoft used to develop its IPv6 implementation. These tools, which you can download from the Microsoft Research (MSR) site (http://research.microsoft.com/msripv6/msripv6.htm), target Win2K and NT 4.0.


If you want support for IPv6 running on a Windows OS earlier than NT 4.0, you'll need a third-party product such as Trumpet Software International's Trumpet Winsock 5.0, which supports IPv6 on NT and Windows 9x. Trumpet also provides a custom Web server (Trumpet Fanfare) and OS (PETROS) built around IPv6.

IPv6 implementation can also occur in embedded system devices, and in the long run it's this type of support that will transform many of the products that affect our everyday lives (e.g., automobiles' onboard computer systems). One player in the embedded-system space is Green Hills Software, which recently announced IPv6 support in its embedded OS and its suite of embedded development tools. Other vendors, such as ARM, also appear to be moving forward with IPv6 support at the embedded-device level.


Migration Support

Tunneling is a key concept in the transition to IPv6. The basic idea is to set up a tunnel from your IPv6 implementation, through the current IPv4 Internet, to other IPv6 implementers. (IETF Request for Comments—RFC—3053 explains the concept in more detail; see "Related Resources" for RFC resources.) Setting up these tunnels is fairly complex and is becoming a market of its own, one which RFC 3053 describes as tunnel brokering.


Two companies working in the tunnel-broker space are Hurricane Electric and Hexago. In addition to their tunnel offerings, each company provides services to help you make the transition to IPv6. Hurricane Electric's services start with an IPv6 tunnel endpoint, similar to the one available from Viagénie. Hexago appears to be concentrating its efforts on providing consulting expertise to help you through the IPv6 transition process. Of course, to take advantage of migration services, you need not only IPv6-compatible software but an IPv6-compatible router. Enter hardware support.


Hardware Support

A complete IPv6 deployment calls for the use of IPv6-enabled network routers, switches, and hubs in addition to support at the software level. Probably not all your existing components will be able to make the transition to the new protocol, but all the major network-hardware vendors have begun to implement IPv6 support.


Nortel Networks has defined an array of IPv6-enabled products, from the entry-level BayStack Access Node/Access Node Hub (AN/ANH) routers to the high-end Backbone Node (BN) routers. Cisco Systems' Cisco IOS Software (12.3 or earlier) doesn't yet support every IPv6 feature but will let you leverage your existing hardware investment as you transition to IPv6. (However, this upgraded IOS has a rather steep memory requirement, so you might find that in the end the upgrade costs almost as much as new IPv6-enabled hardware.) Juniper Networks incorporates IPv6 implementation logic in the JUNOS (5.2 and later) software for its M-series and T-series routers.


Get on Board

So how do you get a new IPv6 address? The Internet Assigned Numbers Authority (IANA) is the ultimate source but delegates control of the process to Regional Internet Registries (RIRs), which in turn distribute addresses to ISPs (see http://www.iana.org/ipaddress/ip-addresses.htm for a more detailed explanation). To find out more about participating in the 6bone IPv6 testbed, visit the 6bone Web site; RFC 2471 describes the basis for the testbed. For more information about 6bone, IPv6, and the vendors who are working to support the new protocol, see "Related Resources." (I recommend starting your research with vendor-related sites, which tend to discuss hands-on topics rather than simply defining the protocol.)


The next generation of the Internet is here, and IPv6 is transforming the underpinnings of the Internet. Expect the market for IPv6 products to continue to grow as more companies migrate their corporate infrastructures from IPv4 to IPv6 and begin taking advantage of the standard's new capabilities.

Contact the Vendors
ARM * http://www.arm.com
Green Hills Software * 805-965-6044
Trumpet Software International
(61) (03) 6245-0220

Viagénie * http://www.freenet6.net
Hexago * 418-266-5533 * http://www.hexago.com
Hurricane Electric * 510-580-4100

Cisco Systems * 800-553-6387
Juniper Networks * 408-745-2000 or 888-586-4737
Nortel Networks * 800-466-7835

Related Resources
RFC 2460: "Internet Protocol, Version 6 (IPv6) Specification"

RFC 2461: "Neighbor Discovery for IP Version 6 (IPv6)"

RFC 2462: "IPv6 Stateless Address Autoconfiguration"

RFC 2471: "IPv6 Testing Address Allocation"

RFC 2473: "Generic Packet Tunneling in IPv6 Specification"

RFC 2474: "Definition of the Differentiated
Services Field (DS Field)
in the IPv4 and IPv6 Headers"

RFC 3053: "IPv6 Tunnel Broker"

RFC 3056: "Connection of IPv6 Domains via IPv4 Clouds"

6bone testbed site


IETF IPv6 Working Group Web site

IPv6 Information Page

IP Version 6 (IPv6)

Cisco Systems


Juniper Networks

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.