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Fujitsu Sees Success in Large-Scale Test of Technology to Solve IPv4 Address Space Exhaustion Issue

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December 11, 2013

Fujitsu Limited, Fujitsu Computer Technologies Limited, the National Institute of Information and Communications Technology (NICT), and the Japan Advanced Institute of Science and Technology (JAIST) today announced that they recently conducted a successful large-scale test of a solution technology that will enable IPv4 addresses to be assigned (shared) to different devices at datacenters configured with IPv6 networks.

The test succeeded at running SA46T-AS(*1) - a technology developed by Fujitsu for sharing IPv4 addresses on IPv6 networks, announced June 12, 2012 - using StarBED(*2), NICT’s large-scale network testbed. For the first time the test confirmed automatic large-scale operations, with no need for manual operation or individual settings, even with virtual servers running SA46T-AS on StarBED.

The success of the test on a large-scale network demonstrated the practicality of SA46T-AS. This, in turn, will make it possible for multiple devices that employ IPv4 addresses - which are still in widespread use despite the fact that IPv4 address space is becoming scarce - to share a single IPv4 address, rather than each needing to be assigned their own separate address. As a result, it will be possible to continue and even augment the use of IPv4.

Details of this technology will be presented at the 6th Internet and Operations Technology Symposium (IOTS2013), to be held from December 12-13 at Hiroshima University.


In recent years, international organizations that manage IP addresses, and relevant organizations in the Asia Pacific and European regions, have noted the exhaustion of the IPv4 address space and, as a result, have promoted the transition to IPv6. At the same time, the ability to continue using existing systems based on IPv4 is a crucial issue, especially for Internet server environments which require the use of IPv4 global addresses. Once IPv4 address space is exhausted, there will be no more IPv4 addresses available for allocation, which is expected to make it impossible to add new servers. Although datacenters and other systems will be designed to run on IPv6 networks in the future, it is still important to ensure an environment on those networks in which IPv4 addresses can continue to be used.

To address these issues, Fujitsu developed SA46T-AS, a technology that makes it possible to share IPv4 addresses and communicate on an IPv6 network. In June 2012 at Interop Tokyo 2012, Fujitsu presented a basic proof of concept for the technology that was carried out as part of a small-scale test among servers. Key to demonstrating the practicality of SA46T-AS technology is the implementation of technology that automatically enables large-scale deployment of virtual servers that use SA46T-AS, with no need for manual operation or individual settings. Moreover, it is also essential to be able to show that performance of the technology in a large-scale environment is sufficient enough to be practical.

Test Results

A large-scale test was performed using NICT’s StarBED environment. With twelve physical servers each running 128 virtual servers, the large-scale test was carried out with a total of 1,536 virtual servers. Results confirmed stable basic operations and scalability, thereby demonstrating sufficient practicality.

Company Roles

Fujitsu: Developed SA46T-AS technology, oversaw test implementation

Fujitsu Computer Technologies: Developed and tested large-scale deployment technologies

NICT: Provided StarBED environment and advised on large-scale virtualization technologies

JAIST: Provided general advice on large-scale testing for the project

The partners in this project are pleased to contribute to the broader Internet community with this “made-in-Japan” technology that supports both the full-scale transition to IPv6 and the continued use of IPv4. As such, the organizations are currently pursuing a standards proposal for the technology with the IETF(*3).

Glossary and Notes

1. SA46T-AS Technology:

Stateless automatic IPv4 over IPv6 tunneling with IPv4 address sharing.

2. StarBED:

A geographically centralized network testbed provided by NICT with more than 1,300 PC servers specifically for testing (as of August 2013). Allocated PC servers and networking resources are available exclusively for users. Users can install any OS or applications they choose, and can configure an overall test environment that suits their purposes.

3. IETF:

The Internet Engineering Task Force. A standards-setting organization for technologies used on the internet, such as TCP and IP.

Press Contacts

Fujitsu Limited
Public and Investor Relations Division
About Fujitsu

Fujitsu is the leading Japanese information and communication technology (ICT) company offering a full range of technology products, solutions and services. Approximately 170,000 Fujitsu people support customers in more than 100 countries. We use our experience and the power of ICT to shape the future of society with our customers. Fujitsu Limited (TSE: 6702) reported consolidated revenues of 4.4 trillion yen (US$47 billion) for the fiscal year ended March 31, 2013. For more information, please see

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