IPv6 (Internet Protocol Version 6), the "next generation" Internet standard, has been under development now since the mid-1990s. Yet despite current testbed activity worldwide, and an emerging push from Asia and Europe, IPv4 (Internet Protocol Version 4) continues to hold sway. As new applications and infrastructure roll out over the next few years, though, more enterprise network managers in the US will face the challenges of IPv6 migration.
So why move to IPv6 anyway, and why the long delay? IPv6 was born out of concern that the demand for IP addresses would exceed the available supply. However, in the US, at least, this hasn't turned into much of a problem at this point.
Most large enterprises have managed to garner large chunks of contiguous IP addresses by nailing down Class A and Class B networks. Protocols such as NAT (Network Address Translation), CIDR (Classless Inter-Domain Routing), and NAPT (Network Address Port Translation) have meanwhile been created, also helping to curb the need for IPv6's new addressing scheme.
Some countries in Asia and Europe, however, are already claiming an IP addressing pinch. "Asia, in particular, is encountering some real problems with address space depletion. IPv4 address space is largely tilted toward the US, because we're the ones who 'invented' the Internet," says Rob Batchelder, research director, Internet infrastructure, Gartner Group.
In fact, the governments of Japan and Korea have mandated national migration to IPv6 by 2005. "I would argue that, by requiring use of IPv6 in these countries, (Japan and Korea) also know they'll get the industry behind it. This will help drive consumption in other parts of the world," predicts John Longo, VP of data services for Global Crossing.
The biggest benefit of IPv6 is replacement of IPv4's 32-bit address scheme with a much longer, 128-bit address scheme. A 32-bit adress scheme allows for a total of 2^32 addresses, while IPv6 allows for 2^128 total addresses. "You'll now have addresses for every penny and every speck of dust," quips Frank Arundell, director of business development at Stealth Communications.
All kidding aside, IPv4 will certainly expand the universe of possible IP addresses for cell phones, PDAs, and consumer appliances, including refrigerators and TV sets, for instance. Some players in the airline industry are even eyeing IPv6 addressing as a possible means of tracking passengers and monitoring airline instrumentation.
IPv6 offers other technical advantages, too. For example, headers will be simplified to seven fields, instead of the 13 fields in IPv4, bringing less overhead than would otherwise be expected from headers for 128-bit addresses.
Header fields will include a "traffic class field," also known as a "priority field," capable of distinguishing between real time traffic such as video and lower priority transmissions that can be slowed down during peak congestion periods.
There are three types of IPv6 addresses: unicast; anycast; and multicast. The new anycast addresses enable a packet sent to a group of anycast addresses to be delivered to one member of the set. IPv6 does away with IPv4's broadcast addresses, rolling their functionality into multicast addressing.
On the security side, IPv6 adds two new extension headers. The "authentication header" provides built-in authentication and integrity (without confidentiality). The "encapsulating security header," on the other hand, supplies confidentiality and integrity..
Despite these and other efficiencies, though, migration to IPv6 is bound to be gradual in the United States. "If migrating to IPv6 was easy to do, it would have been done a long time ago. It's almost like saying that, starting tomorrow, everyone in the United Kingdom will have to start driving on the right hand side of the road. Overnight, you'd have to change all the exits and move all the traffic signs to the other side of the street," notes John O'Keefe, president and CEO of Fine Point Technologies.
Devices with IPv6 protocol stacks will be able to automatically obtain routable addresses. If companies change their ISPs and need to renumber, computers will automatically reconfigure themselves. Still, though, changes will need to be made to router settings, firewall rules, and hard-coded IPs. Global updates to DNS entries will continue to take days to weeks.
The infrastructure for IPv6 is now under way. The IETF (Internet Engineering Task Force), author of IPv6, has finalized the protocol, although approval is still awaited on a number of proposed specifications, including RIPng for IPv6; IPv6 over IPv4 clouds; and FDDI transmission.
Router manufacturers such as Cisco and Juniper Networks have already started to comply with the emerging standard. So, too, have OS like Sun Solaris, Microsoft Windows XP, and Linux.
IPv6 applications are expected to be the strongest driver, but these have yet to appear. Even in the US, however, companies have started to test interoperability and/or applications on testbed IPv6 networks.
For instance, Stealth Communications, a New York City-based ISP, also operates NY61X, an Internet exchange point with links to more than 50 different IPv4 networks and just as many IPv6 nets. The IPv6 interconnects include DEFENSENET; IIJ (Internet Initiative Japan); Sprintlink; UUNET; and Finland's TELIA, for instance.
6bone, on the other hand, is an experimental worldwide IPv6 network. Participants include more than 180 organizations from the US alone. AOL, BellSouth, IBM, Motorola, Microsoft, Xerox PARC, and DREN (Defense Research and Engineering Network) are just a few.