IPv6: What You Need to Know


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.


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Jacqueline Emigh

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