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Concluded Working Groups


IPv6 (Internet Protocol version 6)

  • Theme:Development of the IPv6 world
  • Chair:Kazu Yamamoto
  • Board in Charge:Kazu Yamamoto
  • Expire Date:1999/4/1-2000/3/31
  • Home Page:http://www.v6.wide.ad.jp/

[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

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.

Problem of IPv4:

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.

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.

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.

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.

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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  • SOIリンク
  • AIIIリンク
WIDE Award