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www-admin@wide.ad.jp
Copyright(c) 1988-2000, by WIDE
Project. All rights reserved.
Last update: $Date: 2000/12/20
18:00:00 $ |
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[In Japanese]
[c
o n t e n t s ]
•About IPv6 Working Group
•Problem of Ipv4
•Revolution by IPv6
•Basic principle of the Internet
•Consistency of IPv6 WG
•IPv6 Results of WG
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| About IPv6 Working Group |
The effort for the next generation Internet protocol was started
by Internet Engineering Task Force(IETF) around 1992 in order to
solve the shortage of addresses of Internet Protocol version 4 (IPv4).
SIPP(Simple Internet Protocol Plus) was chosen from several IP candidates
and adopted in 1994. In 1995 it was named Internet Protocol version
6(IPv6), and a basic specification was established.
IPv6 Working Group (IPv6 WG), the WIDE project was started for the
purpose of the deployment of the IPv6 environment in 1995. In the
late of 1995, IPv6 WG had several independent implementations and
held inter-operability test events. Although WIDE IPv6 WG started
later than other reseach institutes, some activities were the first
of the world. An example is carring IPv6 packets on leased lines.
As the specification was verified and inter-operability became common,
it appeared ineffective for IPv6 WG to implement IPv6 stacks independently.
So, the WIDE project started KAME as a subproject for the purpose
of combining the power of implementation. Although the members of
IPv6 WG and KAME overlap, while IPv6 WG does technical and inovative
researches mainly, KAME is in charge of implementation.
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| Problem
of Ipv4 |
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As the specifications of IPv4 have become old, the problems are
mainly the following three points.
1. Shortage of Internet Protocol
address
Because IPv4 is 32 bits, it has about 4,300,000,000 address space
in a decimal number. This amount is absolutely insufficient for
the Internet world wide because it is smaller than the population
of the world. According to calculations by IETF in 1994, that
will exhaust the addresses in about year 2008 +/- 3.
2. Rapid increase of routing
information
When the number of organizations connected to the Internet increases,
the memory and route information increases too. It puts the burden
on the router which forwards the packet, resultiing as increased
memory and decrease at the look-up speed. This could be a fatal
problem for a router with little capacity.
3. Destruction of End-to-end
communication
The end-to-end communication is destroyed by Network Address Translator
(NAT) which was introduced to ease the shortage of addresses.
Therefore, new application developments became less feasible.
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| Revolution
by IPv6 |
What is going to happen when shifting to IPv6? In terms of address
space, IPv4 is about 4.3 x 10^9, being 32 bits. On the other hand,
Ipv6 becomes the astronomical figure of 3.4 x 10^38 because its
length is 128 bits. If the address space of IPv4 is compared to
1 millimeter, the address space of Ipv6 would be 80 times the diameter
of the galactic system. In the world of IPv6, the address becomes
invisible and light as air. Because of the concern for the address
deficiency of IPv4, engineers used to limit their imagination. However,
all equipment could have their address in IPv6, and it is possible
to communicate freely. It is almost mind boggling to contemplate
what services and applications will appear if such an environment
can be achieved.
Now, even the manufacturers of cars and home electric appliances
as well as cellular phones are paying attention to the trend of
IPv6, because by forecast, these equipment will be connected with
the Internet in the near future and will need global addresses.
This problem cannot be solved under the current environment in which
NAT is set up.
In IPv4 there is a strong restraint between the organization and
the provider because changing an address is difficult. Since Ipv6
has been equipped with the function of an automatic setting, the
user's benefit can be expected. In addition, because IPv6 is a protocol
which will spread hereafter, various technologies such as consolidating
IPsec and route aggregation can be assumed to be indispensable.
Objective for the IPv6 WG is promoting IPv6 which has more capacity
over Ipv4 and regaining the basic principle of the internet such
as end-to-end communication and interactivity.
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| Basic
principle of the Internet |
Originally, a basic principle of the Internet is "end-to-end communication"
and "bidirectional communication." It means that both computers
at each end communicate mutually and a router in between does not
participate in the communication.
NAT which was introduced as a technology for the address shortage
destroys this basic principle. Although the IPv4 address was defined
as unique in the Internet originally, it was enhanced as the address
used in the organization can be the same as the address in other
organizations. This is a private address.
The connection with the Internet can be enabled by converting the
private address in the organization into a global address in the
Internet. This address translation device is NAT. It is a situation
in which the middle device which meant to be supporting does rewrite
the content of the communication.
There are many faults of NAT. NAT manages the communications though
it is difficult to share with two or more NAT. Its use is restricted
to to the unidirectional communication. Therefore, it falls into
one point trouble.
NAT should observe the content of the communication. In the protocol
where the IPv4 address is stored, it could rewrite the content of
the communication, but some protocols might not be used. If NAT
in the middle does not function, the excellent applications of the
future become meaningless. Moreover, it is known that compatibility
with IPsec is poor.
Because the private address is not unique, a certain computer within
an organization cannot be specified using the private address from
the Internet. In other words, the communication works only from
inside to outside but not the opposite way around in the environment
set up with NAT. This destroys bidirectional communication, thus
communication becomes just unidirection.
If the foundation of IPv6 is established and a basic principle of
the Internet revives, the user in the end becomes able to conceive
services and the applications freely.
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| Consistency
of IPv6 WG |
Besides the KAME project which specializes in implementation, IPv6
WG works through cooperation with various groups on the vision of
the social life in the next generation. For example, IPv6 WG creates
and tests the model whose specification was developed by the WIDE
project and standardized by IETF; or the manufacturer makes the
router as a product or releases it as a service of the provider
with implementation by KAME. IPv6 WG, the WIDE project might be
the only group with such an integrated system all over the world.
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| IPv6
Results of WG |
There is the misunderstanding among the public that Internet technology
is a United States technology and Japan is mimicking. We are taking
the lead at least for IPv6, and the technology of which Japan can
boast from the research to the system development. We are putting
the effort to spread IPv6 by holding events such as N+I2000 and
IPv6 ShowCase in INET2000 with cooperation in related organization
and related technologies in the world.
Public opinion of IPv6 has been changed lately. Now more people
think"The restriction of the Internet is removed when shifting to
IPv6". A lot of radical changes happened to the situation of IPv6
since the head wind becoming the tail wind in last year. We are
determined to become more active than ever and work harder in order
not to betray people's expectations.
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