Recommended actions for the Japanese ISPs to support the World IPv6 Day


To whom concerning how Japanese Internet community work toward the World IPv6 Day,

Hiroshi Esaki, Ph.,D.,

chairman, IPv4 Address Exhaustion Task Force, Japan


1. Current Status of IPv6 Internet Access Networks in Japan

The Japanese ISP industry has been working hard to introduce and to deploy IPv6 Internet access service, as one of the major counter measure to IPv4 address depletion. Following some IPv6 Internet access services for corporate users, the residential IPv6 consumer services were started by many Japanese ISPs since last year, e.g., in addition to the OCN service by NTT Communications, which launched IPv6 tunneling service in 2007.
In 2010, Softbank BB, which has 9.7% market share in broadband access service in Japan, launched IPv6 Internet access service in 2010. The most popular FTTH Internet access service in Japan, i.e., Flets Hikari Next by NTT East and NTT West announced two types of IPv6 internet access for VNOs; i.e., (1) Tunnel Configuration and (2) Native Configuration. The Tunnel Configuration type service was scheduled to start in April 2011, however, it was postponed for one or two months, due to the series of urgent tasks for NTT group and due to damages on factories for related components to assemble equipments to provide these services caused by the serious earthquake in Tohoku area on March 11th 2011.
On the other hand, KDDI, which has about 9% market share in FTTH Internet access, announced that they will launch IPv4/IPv6 dual stack Internet access service from April 18th.


2. Principles and the original plan/strategy toward the IPv6 Day for Japanese Internet society

The World IPv6 Day is planned as a single day trial with 24 hours only. However, we have to realize that the transition from IPv4 to IPv6 or the introduction of IPv6 into the existing Internet is the way to be taken by all the stakeholders constituting the Internet system. They do not only include Internet Service Providers and Internet access providers, but they also include Contents Service Providers, Private/Corporate networks and individual residential users. When any problem occurs during the introduction process of IPv6 services, it should be resolved. The end users should prepare their local environment so that they can access the Internet using IPv6, ISPs should provide IPv6 Internet access reachability to end users and the service provides should provide services with IPv6. Such environment is our goal. However, we have to realize that the networks and services to achieve this goal has not yet been widely deployed at this moment and it is estimated that it will take at least a few more years until a large portion of the end users can fully introduce IPv6 environment.

3. Measures in Japan toward the First World IPv6 Day

To overcome the technical and operational issues that may occur on the World IPv6 Day, the following actions will be applied to Japanese ISPs.

(a) Introduction of polity table feature into the end nodes

In Japan, NTT East and NTT West allocate IPv6 address to end users only for their local services,.All the terminals using these services have IPv6 address, that are automatically assigned. This means that, when an Internet service site adds an AAAA record to its DNS, the terminals will try to use the IPv6 address to access such site. If the ISP for such user provides IPv6 Internet access, the well-known multi-prefix problem shall occur. When the ISP does not provide the IPv6 internet access, the fall back to IPv4 may occur to lead to around 30 seconds access delay. In the worst case depending on the implementation at the end user terminal, the communication may be terminated.
This problem can be avoided by enabling of the policy table defined by RFC3484. Since it is generally difficult for a consumer user to develop/implement such policy table, some Japanese volunteers are working to provide a software to configure the policy table automatically, which is expected to be distributed before the first World IPv6 Day (June 8th 2011).

(b) Introduction of AAAA filter as a "temporary" solution, i.e., emergency evacuation measure

To avoid the access latency, lower throughput or the termination of TCP connections caused by the fall-back operation by the end user terminal, in a local only IPv6 environment descried above in Japanese access networks, we will suggest the introduction of the following function as an emergency evacuation measure for the service providers, that cannot provide the IPv6 connectivity to the end users on June 8th. It is to filter the distribution of AAAA record to end user terminals not having IPv6 connectivity. In other words, we suggest to introduce a filter into DNS to report AAAA only when access by the end user terminal to DNS is performed by IPv6 transport.
The filter is available on Bind 9.7 and later. Such AAAA filter will be introduced into the ISPs in Japan, who will not be ready to provide IPv6 transport service by the first World IPv6 Day.

(c) Fallback solution

When the policy table is not introduced and the corresponding ISP does not provide the AAAA filter, the fallback to IPv4 from IPv6 might occur and the users will use IPv4 transport with some latency. The ISPs in Japan recommend to support such behaviors for all end user terminals. An open subscription working group is established to provide a guideline for ISPs so that they can support the end users on the first World IPv6 Day.


4. Conclusion

As we have a variety of Internet access environment in Japan as well as in the world , Japanese ISPs are trying to resolve the identified technical and operational issues related to the introduction of IPv6 into the market, such as multi-prefix problem between a closed network and the global Internet. In Japan, verification of these issues in the various environment is under progress and we hope that we will be able to provide the results and their practical solutions by the first World Ipv6 Day. Due to the serious earthquake occurred on Marchi 11th 2011, we may not be able to have a large dual stuck Internet access environment on the first World IPv6 Day. However, after the first World IPv6 Day, we estimate that the penetration of IPv6 service in Japan will grow and we will see more end users accessing IPv6 sites.
We are fully committed to offer and to provide the knowledge and experience we will acquire through the trial via IETF RFCs and BCPs to feedback the global Internet community.

What's IPv4 Exhaution



  • ICT Education Promotion Council of Japan
  • IPv6 Promotion Council
  • Internet Association Japan
  • Communications and Information network Association of Japan
  • Association for Promotion of Public Local Information and Communication(APPLIC)
  • Local Authorities Systems Development Center (LASDEC)
  • Telecom Service Association
  • Telecommunications Carriers Association(TCA)
  • Japan Cable and Telecommunications Association
  • Japan Cable Laboratories
  • Japan Data Center Council
  • Japan Network Information Center
  • Japan Network Operators Group
  • Japan Network Security Association
  • Japan UNIX Society
  • Japan Registry Services Co., Ltd.
  • Institute for HyperNetwork Society
  • WIDE Project
  • Ministry of Internal Affairs and Communications

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