Connectivity:General
Understanding IPv6
The upsurge in use of the Internet has lead to an increased requirement for IP numbers,
which are rapidly running out. A new standard for IP numbering is about to be introduced
to help overcome some of the limitations of the old system and to provide enough addresses
to see us all well into the next century.
By David Morton
M
any of us have heard of the
At the same time IPv6 attempts to
of addresses that would be required,
proposals to convert the In
address one of the largest headaches of
back in 1991, when it was still known
ternet
Protocol standard
an IP network from the administra
as the Internet Activities Board. To
from the current version IPv4 to a new
tor's point of view; configuring the net
some extent the growth had been an
standard. Few of us are really aware of
work in the first place. Despite time
ticipated everyone knew there would
all the implications. The driving force
saving systems like BOOTP and
be ever more computers connected to
of the new standard is the rapid
DHCP, a huge number of networks are
the Net. What was less obvious then
growth of the Internet and IPv6 is be
hand crafted, with IP numbers typed
was that the Net would extend beyond
ing introduced to overcome the ad
in at individual workstations by unfor
computers in the conventional sense,
dress space restrictions of the old one.
tunate support staff whose job is to do
and that there would soon be a require
At first glance the implications for the
little else. Anything that automates
ment to assign IP addresses to devices
network administrator seem negli
this process will help, and IPv6 goes a
as diverse as mobile telephones, other
gible, because many of us already have
long way in this respect.
communication devices and even mo
our allocated addresses. In some cases
Many network administrators dis
tor cars. There is already a car on the
we've enough to last us for a consider
like changes like IPv6 because they fear
market with a built in modem for di
able period of planned growth, so why
some hideous one day change over
agnostics, and no doubt more will fol
should we be interested in IPv6?
that leaves life chaotic for days or even
low.
IPv6 is a lot more than IPv4 with a
weeks afterwards. Thankfully this
These early studies lead to the ap
couple of numbers bolted on the end
shouldn't be the case, since an IPv6
pointment of a team of engineers and
to make the address space bigger. It's
network can talk to an IPv4 network
scientists, working under the Internet
a ground up re think of what will be
and vice versa. If you have two sites
Engineering Steering Group, charged
required from IP as a protocol in the
with an IPv6 system, and your Internet
with defining the next generation In
future. IPv6 starts to take on board the
connection between the two is only
ternet protocol. This group co ordi
modifications that will be needed to
IPv4, then the two networks will still
nated the efforts of a number of other
cope with the changing traffic that will
be able to talk the IPv6 packets tun
teams studying the problem of address
start to appear on IP networks glob
nelling through the IPv4 connection.
space size, enhancements to the Trans
ally. It is anticipated that there will be
So there are few reasons to fear IPv6,
port Control Protocol (TCP) and the
much more emphasis on real time
and every reason to start planning the
problems of compatibility with other
transactions as the Internet and intra
changes now.
protocols notably IPX.
nets metamorphose from old style
After due deliberation, the first pro
data networks, into complex transmis
History
posals were documented in the usual
sion systems carrying a vast wealth of
manner for Internet enhancements a
data, entertainment and other services,
The Internet Architecture Board
Request For Comments (RFC number
some not yet even a twinkle in their
started studying the problem of the
1752) entitled The Recommendation
innovator's eye.
growth of the Internet, and the number
for the IP Next Generation Protocol ,
issued in 1994. It took a year for these
proposals to be finalised, which finally
RFC1883 The IPv6 base protocol.
happened in July 1995.
RFC1884 The address specification.
January 1996 saw the publication of
RFC1885 Description of the control protocol, known as ICMP.
the detailed proposals, in the five fur
RFC1886 Addressing the problems of an enhanced Domain Name Service
ther RFCs detailed in Figure 1. After a
(DNS).
brief pause, perhaps the most vital
RFC1933 The transition mechanism.
RFC was issued in April 1996.
RFC1933
covered
the
transition
mechanism how to switch over from
Figure 1 RFCs covering the detailed proposals for TCP protocols.
one system to the other without the
Issue 83 (May 1997) page 17
File: C0655.1
PC Network Advisor
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