NTT Technical Review
October 2013 Vol. 11 No. 10
View from the Top
Akira Arima
President & CEO, NTT Communications

Feature Articles:
NTT I3—Seeking to Actively Develop Global Cloud Services
NTT Group Global Business Strategy and NTT I3
Enhancing Security Analysis at NTT I3
Networking at NTT I3 and Outlook of SDN

Regular Articles
Load Modulation Applied to Magnetic Resonance
Wireless Power Transfer Technology and Its Applications
Reducing Electric Power Consumption for
Air Conditioning by Improving Temperature Distribution
in Telecom Equipment Rooms

Global Standardization Activities
IEEE 802.11 Wireless LAN Standardization Trends

Practical Field Information about
Telecommunication Technologies
Case Studies of Recent IP Problems in HomesView from the Top

The Cloud as Trigger fora Global Strategy Leveraging
the Strengths of a Telecom Carrier
Akira Arima,
President & CEO, NTT Communications
Overview

NTT Communications is taking up the challenge of creating new businessunder its Vision 2015 growth strategy. What kind of approach is needed toachieve true globalization in an ICT market that demands quick results? We
asked President & CEO Akira Arima to tell us about current trends in the
ICT market and the strategy of leveraging the strengths of a telecom carrierin the field of cloud services.
Keywords: telecom carrier, cloud services, strategy

Providing global and total ICT outsourcing services
as only a telecom carrier can—Mr. Arima, in the three years since you took up yourpresent position, how has NTT Communications been
progressing?
These last three years have been a period of transition for our business. As for sales, operating revenue
for the 2012 fiscal year of the NTT Communications(NTT Com) Group could not help but fall due to a
structural decrease in revenue in voice communications and a revenue drop accompanying fierce pricecompetition in the data-network business. Unfortu­
nately, revenue increases in cloud services and othergrowth fields could not cover this decrease in revenue. Although we have not been able to apply a braketo this overall decrease in revenue, we neverthelessachieved a record operating profit since the foundingof the company, following the record profit in fiscal
year 2011. The issue we face now is boosting our
topline growth. My goal is to increase our revenues
without a moment’s delay.
I feel that the efforts I have made since taking up
this position in greatly restructuring the company’s
internal organization and making business processes
more efficient are putting the company on the rightpath to profits.
Although the things that I want to do have not inessence changed since the time that I assumed thisoffice, the pending issue is how to create new business as a means of increasing revenues, which is thefoundation for growing profits under Vision 2015.
Looking forward, I will promote global and total outsourcing services befitting a telecom carrier as anopportunity for our customers to convert their information and communications technology (ICT) to thecloud under our Global Cloud Vision.
—Please tell us how you plan to position and execute
the Global Cloud Vision business strategy.
I believe that achieving corporate growth solely on
the basis of the Japanese market is very difficult.
Adding the word “global” to our strategy reflects mydesire to make the provision of cloud services on aworldwide basis a core strength of our company.
As for the cloud, I can say that there are many
NTT Technical Review

View from the Top

diverse ways of implementing and providing cloudservices, and there are many companies competing inthis field. Developing services that can differentiate
NTT Com from other companies is essential. For us,
the cloud, in the end, is a trigger. My aim in leveraging our strengths as a telecom carrier is not simply toprovide cloud services but also to provide global andtotal ICT services that include our networks and datacenters connected to the cloud as well as general-purpose applications, security, operations management,
and other attractive services.
Demonstrating all our strengths inproviding total ICT services—It would appear that safety and security are strong
requirements in operating a cloud. What are yourthoughts on this?
As companies continue to adopt ICT at an accelerated pace, it becomes more important than ever tomaintain a safe and secure network environment.
For example, while a datacenter operator would
ensure the reliability of the datacenter itself by securing a stable supply of power, our strength as a telecom
operator would be to comprehensively provide total
ICT services in a safe and secure manner. Somepeople probably have the idea regarding this strengththat instead of a comprehensive, total provision of allservices, it would be better for the customer himself
to assemble a set of services from among those considered to be the best in the market in each field, suchas the infrastructure, datacenter, or network field.
An ICT system, however, would generally become
unusable if any one of its constituent components—
such as the cloud, datacenter, or network—fails. Ourstrength lies in our ability to provide services underan ICT system that is totally under our control. For
this reason, we pay close attention to maintaining
close ties between the various sections within NTT
Com so that we can fully demonstrate to our customers our strength in being a one-stop provider of services. Furthermore, as a dedicated network operator,
we can embed the cloud within the network, whichmeans that we can provide a cloud connection as afree service. While other operators charge for such aconnection, we can provide it for free.
At present, we provide the same services in various
regions around the world. We feature 146 global datacenters including those scheduled to be launched next
fiscal year, and we have clouds set up in 10 bases
spanning 8 countries. Moreover, to differentiate ourVol. 11 No. 10 Oct. 2013

clouds in the marketplace, we are rolling out functional enhancements such as automatic cloud migration (on-premise connection service), automatic virtual private network (VPN) connections, and integrated customer portal sites based on softwaredefined networking (SDN). We are also working on
expanding our Wide Angle managed security service,on rolling out a new security platform (security information and event management (SIEM) engine) in 9
countries, and on setting up a security monitoring
system at more than 450 locations in 14 countries.
These initiatives have been highly evaluated bythird-party institutions. In just this past year, forexample, NTT Com received the Best Cloud-based
Service and Best Asian Telecom Carrier award at the
Telecom Asia Awards 2013 (held April 2013) and theGrand Prize in the Security Services section at the
MM Research Institute Awards 2013 (held in June2013).
The inroads made into foreign markets by Japanesemanufacturing firms and other enterprises have been
truly remarkable, and we have not a few customers
who obtain more than half of their profits from overseas operations. These customers are faced with avariety of issues resulting from M&A (merger andacquisition) activities with overseas companies suchas the need to merge ICT systems and achieve greater
operational efficiency. We are frequently receiving
inquiries on whether we can provide the same qualityof service overseas as in Japan and whether we can
support global activities. If we cannot support ourView from the Top

customers in these ways, we will not be able to survive.
In addition, when thinking about our own transformation into a global enterprise, we will, of course, be
providing services throughout the world from overseas bases, but I think that there is also a need toreform the company from inside Tokyo headquarters.
One issue, for example, is the ratio of foreign employees. Ideally, there is a need for foreign representation
at the executive level, but our efforts will begin with
developing a multinational group of employees.
Face reality objectively and choose decisivenessover hesitation—NTT Com’s desire to globalize is understandable
given the times and current trends, but moving withtrends also involves some unknowns, which meansthat risk too must be taken into account. How do you
assess risk?
Work at the executive level is, in one sense, an
ongoing assessment of risk. As to whether one should
hold back or more forward, I think it is better toadvance than to stay still once the risks have beenthought out. With cloud services, for example, wewere confident that there was a real need for these
services after reading market trends, so we felt that it
was then just a matter of matching our expertise andbusiness model with those needs.

Multinational companies in various countries
around the world are now focusing on the Asia market. They’re investing in Asia as a growth strategy, butwhen deciding where to establish a hub, their attention is unfortunately drawn not to Tokyo but to Hong
Kong or Singapore. We nearly sold out the capacityof the datacenter we launched in Hong Kong in May
to customers consisting of foreign corporations.
It is natural to keep in mind such data or feedback
that can serve as grounds for decision making, but topromote even further growth, it is essential that onsite visits be made to collect comprehensive information as a basis for making intuitive decisions. For thisreason, I see to it that we make fact-finding missions
to our colleagues’ sites scattered throughout theworld to hold discussions and find out what our customers really need.
There is always the risk that some sort of problems
will arise when expanding business, so it cannot be
said that everything is going fine—there is no otherchoice but to deal with those problems accordingly. I
believe that facing reality objectively is very important. Since we are always competing with other carriers for business, we must be able to respond to customer needs in a timely manner. The time limit for
doing so is set by the market, and if we cannot propose solutions by that time, we will have achieved
nothing.
—What is the state of collaboration with NTT R&D(Research and Development), which supports thebusiness of NTT Com?
We are now in the process of receiving support
from NTT laboratories as we convert the cloud infrastructure to a virtual network. While it might be easy
to say that a “customer’s existing system should be
migrated to the cloud,” doing so would normally
involve lots of hard work. In contrast, our approach is
to construct a virtual network between our datacenterand the customer’s system and use it to move thecustomer’s system directly to our cloud. Thisapproach has received high marks from various quarters in the industry as the world’s first auto-migration
system.
Additionally, in the area of security services, wehave developed a SIEM engine combining the knowhow of NTT Com and NTT Com Security and theadvanced technologies of NTT laboratories and have
deployed it as a new security operations infrastructure. By adding blacklists that incorporate NTT Com
proprietary know-how to this SIEM engine, we have

NTT Technical Review

View from the Top

made it possible to reliably detect and deal with security risks such as by visualizing unknown threats thathave previously been difficult to detect.
On the basis of these activities, we can say thatwithout NTT laboratories we would not have these
attractive cloud services to offer. I would hope that
this use of research results in the business of NTT
Com being a source of motivation for NTT researchers. I would like to strengthen our collaborative
efforts with NTT R&D to provide products and services that draw responses such as “NTT technology
is amazing” from customers around the world.
Differentiating NTT Com from its competitors
by automating routine tasks andeliminating operating mistakes—Mr. Arima, could you leave us with a message for
all NTT Com employees?
In this era in which results are needed promptly, theprovision of services is meaningless if they are notprovided when needed. In this regard, the services
that we can provide at that time will not always satisfy all customers. Even if 100% of our customers
cannot be satisfied, it is important that we provide
services promptly in a way that comes as close as
possible to 100%.
This holds true for cloud services and network services. There are many cases in which competingcompanies are providing services using similar technologies, so how can we differentiate our services?
The key is to provide an operation system and findways of making operations more efficient. To thisend, we are pursuing automation aggressively and areworking, in particular, to automate routine tasks to
cut down on as much human intervention as possible
and eliminate operating mistakes.
I think that we are gradually achieving results andVol. 11 No. 10 Oct. 2013that customers are coming to use our reasonably
priced services with confidence. We cannot allow
ourselves to think that there is a market with no competitors. It is imperative that we quickly identify the
problems enveloping our customers and that we deal
with them promptly and appropriately.
Interviewee profile
Career highlights
Akira Arima joined Nippon Telegraph andTelephone Public Corporation (now NTT) in
1973 after graduating from Hitotsubashi
U n ive r s i t y, Fa c u l t y o f C o m m e r c e a n dManagement. He served as Senior Vice President
and Executive Manager of the Corporate Strategy
Planning Department of NTT EAST, Senior Vice
President of NTT, and Senior Executive Vice
President of the Net Business Division, NTT
Communications Corporation, before taking up
his present position in June 2010.

Feature Articles: NTT I3—Seeking to Actively Develop
Global Cloud Services

NTT Group Global Business Strategy
and NTT I3
Eiji Kuwana
Abstract

NTT’s Medium-Term Management Policy Towards the Next Stage calls for the early development andmarketing of world-class cloud and security technologies in North America, the most competitive market
in the world. To achieve this objective, NTT Innovation Institute, Inc. (NTT I3) was established on April 1,2013 as a research and development center in North America. This article introduces the NTT Group’s
global business strategy and the role of NTT I3 in executing this strategy.
Keywords: global, security, cloud

1. Introduction
NTT’s Medium-Term Management Policy Towards
the Next Stage, announced in November 2012, introduced the goal of becoming the value partner that
customers continue to select. The policy also
describes two pillars of this new effort that are central
to achieving this goal: global cloud services as thecornerstone of NTT’s business operations, and highly
competitive network services.
Global business is the driver of NTT Group growth.
The stated goals are to double global earnings overthe next five years, and in 2016, to earn $20 billion,
with more than 50% of corporate earnings comingfrom global business.
To grow its global business, the NTT Group plansto enhance its consulting and solution-proposal abilities in order to implement effective solutions to its
customers’ business problems through informationand communications technology (ICT). Thus, inaddition to providing existing ICT services, there is aneed for boosting paradigm-shifting services with anemphasis on cloud services, mobility services, andadvanced analysis of diverse business data for prediction purposes (business analytics). There is also aneed for operating ICT services and business processes in an end-to-end manner and for creatingstrong relationships with customers as a path to newservice provision. The need is likewise felt to provide

flexible and high-quality services that can combine
the customer’s existing information systems with
NTT’s cloud service menu and even with services ofother companies (Fig. 1).
The NTT Group has formulated a system thatdrives a full lineup of business areas combining networks, datacenters, managed ICT, applications, solutions, services, and research and development (R&D)(Fig. 2). As reflected in the phrase Next Value Partner
for Transformation by Total Solution (NTT), the NTT
Group seeks to gain the trust of its customers byoffering differentiated services and technologies thatcan support the transformation of their business models.
NTT may be a trusted brand in Japan, but from a
global perspective, it is ranked number 2 among
Japanese companies and number 16 among all companies in all industries in the world as announced by
Brand Finance in its brand rankings [1]. While thisbrand recognition is certainly not unfavorable, there
is still much room for improvement. To gain trust on
a global scale, it is essential that NTT invest aggressively in new fields such as cloud computing andsecurity and expand its global business.
2. Purpose of establishing NTT I3
NTT I3 was established on April 1, 2013 (Fig. 3) aspart of the NTT Group’s push toward globalization as
NTT Technical Review

Feature Articles

Existing IT(information
technology) systems

ICT services
Developed countries
Developing countries

Advisory services

On-premise

Wi-Fi

Mobilenetwork(1) Existingcustomers

Big data

Security

M2M

Global network

System visualizationfrom applications todevices

Security

Cloud platform

Security
management

Global datacenter/network
Wi-Fi

Propose composite
business analysis and
ICT services.

(2) New
customers

Standardized
cloud etc.

Cross-industry platform

Mobility

Infrastructure

Business analytics

Platforms

Off-premise

Migration of businessapplications to cloud

Cloud

Applications

ICT management

Business
processes

Mobile network

Provide flexible and high-quality ICT services
including other companies’ services.

Propose end-to-end, secure
ICT/business-process
management.

Support customer’s business transformation as an ICT strategic partner.

M2M: machine to machine

Fig. 1. Global business development in the NTT Group.

Sales: ¥10.7 trillion
No. of employees: 224,000
No. of group companies: over 770,
as of March 2013
Advisory services

Migration services

Operation services Management services

Applications

Solutions

Services

Customers

Managed ICT

Datacenters

Networks

R&D

Fig. 2. NTT Group overview.

described above.
NTT I3 seeks to become a global hub of NTT R&D
and to provide new service creation to support theVol. 11 No. 10 Oct. 2013

growth of the NTT Group’s global business. To
achieve this goal, it will focus on four activities, assummarized below.
Feature Articles

New North America R&D center
NTT Innovation Institute, Inc. (NTT I3)

Fig. 3. Map image depicting establishment of NTT I3 as one of NTT’s global holdings.

(1) Establish a market foothold: North America isconsidered to be an advanced region in terms of security, cloud computing, and other ICT technologies.
By establishing a foothold in this market and developing competitive skills in North America, NTT I3
can expand to other regions where markets can be
opened up and can enhance its competitive skills in a
wider variety of regions.
(2) Leverage the Silicon Valley ecosystem: Silicon
Valley is a center of leading technology companies
and a repository of information on cutting-edge technology. It is consequently an ideal location for developing strong partnerships with forward-looking
companies and for quickly collecting information on
advanced technologies. NTT I3 will pursue service
development making best use of the advantages ofthis region.
(3) Develop intellectual property (IP) for corporate
global business: Being in close proximity to theNorth America market, NTT I3 aims to convert technologies matching the businesses of NTT Group
companies in North America into IP as quickly as
possible and to bring that IP to this market. The overall plan is to modularize this IP and market it globally.
(4) Be a source of differentiation for the NTT Group:
A key strength of the NTT Group is R&D, and theestablishment of a center in North America is a major
step forward for NTT in expanding its R&D. NTT I3
aims to raise the level of product differentiation in the
NTT Group by promoting applied R&D that can only

be carried out in North America based on market
needs while incorporating the results of basic researchand development at the NTT laboratories of NTT
Holding Company. Furthermore, while some service
development has traditionally been undertaken under
the separate visions of the various NTT Group companies, the promotion of applied R&D by NTT I3 in
the North American market is expected to contributeto group collaboration and to produce a synergetic
effect among the NTT Group companies.
3. NTT I3 approach to R&D
To meet the needs and desires of more than 10,000
enterprise clients around the world, NTT I3 seeks todevelop IP in cloud, security, mobility, and operations
technologies with the aim of developing innovative
services and providing superior operations (Fig. 4).
In particular, NTT I3 focuses on innovations that
contribute to the business agility of our clients. Business agility is built on five capabilities: (1) Exploring
innovative technology-enabled business models, (2)responding rapidly to emerging competitive threats,(3) improving the speed at which these business models can be brought to the marketplace, (4) dealing
with regulatory, security, and privacy threats in an
increasingly connected global marketplace, and (5)doing all of these at a price that provides value to theircustomers and stakeholders. Today’s organizations
cannot compete successfully in the dynamic global
marketplace without these capabilities.
NTT I3 recognizes our clients’ critical need forbusiness agility and therefore drives innovation inthree layers. Innovations at the top layer should
NTT Technical Review

Feature Articles

Technology enabled innovation(industry-as-a-service solutions)
DevOpS4Cloud

Customers’
current
environment

Application
migration
to cloudAgiledevelopment(building andenhancing
applications)

Cloud

Security

Managing/
supporting
environment(smart
MSP/MSSP)

Innovation for infrastructure:
software-defined DC,
cloud–VPN gateway automation,
malware/threat detection,
secure data on cloud, etc.

DC: datacenter
MSP: managed service provider
MSSP: managed security service provider
VPN: virtual private network

MobileAnalytics

Fig. 4. NTT I3 approach to R&D.

redesign our clients’ business models and/or businessprocesses. Innovations at the middle layer should
accelerate our clients’ activities of developing andoperating new applications while providing up-todate security protection. Innovations at the bottom
layer should advance our infrastructure to provide
services at software-speed while achieving high performance and security.
For the present, NTT I3 will focus on service andproduct development in the areas of security andcloud computing. The following describes specificdevelopment efforts in these two key areas.
3.1 CloudA strong point of the NTT Group’s cloud is that awide range of services can be provided. For example,
the NTT Group can provide total customer support
throughout the life cycle of cloud-migration planning, migration execution, and post-migration operations. These services cover all layers, i.e., the application, cloud platform, and network layers. Anotherstrong point is that the NTT Group has an R&D
department for cloud development. The NTT Groupstrategy seeks to leverage these strengths, and in linewith that strategy, NTT I3 will work to develop IP thatcan extract the synergy among the wide range of services that the NTT Group provides (Fig. 5).
At present, NTT I3’s work in cloud computing canbe divided into three main themes. The first theme iscloud migration support technology (migration technology). This technology is being developed toVol. 11 No. 10 Oct. 2013

reduce barriers at the time of migration and to
improve stability in performance. The second themeis big-data analysis technology for managing the performance of applications. With this technology,
NTT I3 aims to help customers maintain high application performance by identifying the dependencies
among multiple performance metrics of a complex
cloud environment. The third theme is network andstorage technologies for cloud computing. In particular, NTT I3 is working intently on software-defined
networking (SDN) technology, which is essential to aservice provider like NTT for creating differentiatedservices. For more details, please see the example of
SND presented in “Networking at NTT I3 and Outlook of SDN” [2] in these Feature Articles.
By approaching R&D in the above way, NTT I3 will
first aim for growth in the NTT Group companies
doing business in North America while also planningto roll out the IP developed and recognized in thismarket to developing countries and Japan itself sometime in the future.
3.2 Security
Security measures and security analysis and management are undergoing changes due to a number offactors including changes in the types of threats andvulnerabilities, changes in the legal system and social
demands, and the influence of stakeholders. The NTT
Group aims to establish a permanent position foritself as a top-class security integrator in the world by
providing comprehensive managed security services
Feature Articles

Businessmodels &processes

Cross-application integration

Application
environment

Application
migration
automation

Orchestration
Infrastructure

DevOpsincludingtesting aaS

Application
performance
management

Operation and management

Storage

SDN
aaS: as a service
DevOps: development and operations

Fig. 5. NTT I3 development efforts in cloud computing.

Cloud &
mobileapplications- Email sender authentication- Resilience & application security
testing- Customer-controllable data
management- Security policy development

Operation &management- Semantic-based security
monitoring (powered by big data
analysis)- Visibility as a Service- Device & behavior monitoring- CERT as a Service- CSIRT training program

Platform- Deep security & malware analysis- Identity & access management- Software-defined security- Cloud data encryption & key
management- Smart device security- Global security intelligenceplatform

Resilient security forbusiness agility

Business data transformation
to the cloud/security
enhanced mobility

Secure & reliable service

Fig. 6. NTT I3 development efforts in security.

encompassing consulting, operations, and platforms.
To support this endeavor, NTT I3 plans to construct
a global security platform that will serve to enhance
the security businesses of NTT Group companies.
This plan includes the development of a Deep Security Analysis Platform for analyzing threats and an
NTT Global Security Intelligence Platform for disseminating information on threats and vulnerabilities(Fig. 6). Incidentally, there is already a history at
NTT I3 of analyzing security intelligence in collaboration with NTT’s Computer Security Incident
Response and Readiness Coordination Team (NTTCERT) and Computer Security Incident ResponseTeam (CSIRT) organizations throughout the world.
NTT I3 aims to leverage its experience in these activities to research and develop advanced security technologies. A more detailed description of this endeavor
can be found in the Feature Article entitled “Enhancing Security Analysis at NTT I3” [3] in this issue.
References[1][2]

Brand Finance 2013 rankings.
http://brandirectory.com/league_tables/table/global-500-2013
R. Raszuk, “Networking at NTT I3 and Outlook of SDN,” NTT Technical Review, Vol. 11, No. 10, 2013.

NTT Technical Review

Feature Articles[3]

https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr2013
10fa3.html
S. Adachi, “Enhancing Security Analysis at NTT I3,” NTT Technical
Review, Vol. 11, No. 10, 2013.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr2013
10fa2.html

Eiji Kuwana

Chief Operating Officer, NTT Innovation Institute, Inc.
He joined the Nippon Telegraph and Telephone
Public Corporation (now NTT) in 1984 and hassince held positions of increasing responsibility
in research, engineering, and management. Most
recently, he led NTT’s R&D efforts on cloudtechnology, and information and network security technology as the Vice President and General
Manager of the former NTT Information Sharing
Platform Laboratories and NTT Secure Platform
Laboratories. He was in charge of formulating
strategic plans for various innovative R&D projects such as building flexible cloud environments
by enabling live migration between different
datacenters through software-defined networking.

Vol. 11 No. 10 Oct. 2013



Feature Articles: NTT I3—Seeking to Actively Develop
Global Cloud Services

Enhancing Security Analysis at
NTT I3Shin Adachi
CISSP, CISM, CISA, PMP
Lead Security Analyst,
NTT Innovation Institute, Inc.
Abstract

NTT Innovation Institute, Inc. (NTT I3) has been analyzing security intelligence in collaboration with the NTT Computer Security Incident Response
and Readiness Coordination Team, also known as NTT-CERT, and other
CSIRTs, or Computer Security Incident Response Teams, and it aims toapply this know-how to the research and development of advanced security
technologies. We asked Shin Adachi, the Lead Security Analyst at the centerof security-related work at NTT I3, about the current status of information
security and the benefits of establishing NTT I3 as a center for research anddevelopment in North America.
Keywords: security, CSIRT, security research

Introduction
A Computer Security Incident Response Team(CSIRT) works to prevent (if possible), detect,
respond to, and mitigate security incidents, including
cyber attacks on companies and organizations. In
large corporations or in companies operating a critical infrastructure, it may be a dedicated organizationconsisting of a full-time staff or team whose members
hold concurrent posts in the company. The NTT
Computer Security Incident Response and Readiness
Coordination Team, also known as NTT-CERT, waslaunched in 2004 within NTT R&D (research anddevelopment) of NTT Holding Company as the
CSIRT representing the NTT Group. It supports the
NTT Group in security-related matters, including theprovision of up-to-date information, and acts as an
NTT Group contact point for interacting with outside
security organizations and collecting information.
NTT I3 has been supporting the monitoring func

tions of NTT-CERT since 2012 originally in the formof its predecessor, NTT Multimedia Communications
Laboratories (NTT MCL). Specifically, it has been in
charge of surveying security conditions especiallyoutside Japan and of maintaining and boosting interaction with outside organizations (Fig. 1). Given that
security and cloud computing are major areas of
R&D at NTT I3, this work can be expected to take on
an increasingly important role in the years to come.
Shin Adachi, the Lead Security Analyst at the center of this work, is well known for his activities inmajor security-industry organizations including theForum of Incident Response and Security Teams(FIRST)—the global forum of CSIRT organizations—and is recognized internationally as a security
expert. Last year, he was elected co-chair of the
FIRST Education Committee, one of the oldest committees in FIRST, succeeding his predecessors fromthe CERT Coordination Center (CERT/CC) at Carnegie Mellon University, which is known as the first
NTT Technical Review

Feature Articles

NTT-CERT (NTT I3)
Interaction with outside organizations

R&D

FIRST

Education/training

Analysis

SupportDetection
Information sharing,
contact pointCSIRT
JPCERT/CC
Self-monitoring

NTT Groupcompanies

Honeypots etc.

Fig. 1. Overview of NTT-CERT (NTT I3) activities.

CSIRT. Mr. Adachi was elected as co-chair together
with Franz Lantenhammer, head of Computer Emergency Response Team Bundeswehr (CERTBw) of theGerman Federal Armed Forces. He is the first Committee Chair elected from a company based in Asia.
The CSIRTs belonging to individual companies ororganizations form human networks to create mutually trustworthy relationships, which are often
reflected in daily activities such as obtaining reliable,
up-to-date information from that network and working together to deal effectively with security incidents. Mr. Adachi has a large network of personal
relationships and extensive experience in the security
industry, and his NTT I3 colleagues often refer to him
as “our treasure” for this reason.
—Mr. Adachi, can you tell us about the present stateof cyber attacks?
To begin with, let me say a few things about theseincidents that we call “cyber attacks” considering that
we don’t usually know from whom or where, or how
an attack will be mounted.
The first thing that probably comes to mind when
hearing the words “cyber security” is attacks on personal computers (PCs). However, it was not so long
ago that an attack was made on the Subway restaurant
chain in the United States in which a vulnerability intheir POS (point-of-sale) terminals was exploited.
This attack caused considerable damage and was later
found to have originated in Romania.
If we look at recent trends, survey reports and security-related literature tell us that there is a considerable time lag between the first occurrence of a malVol. 11 No. 10 Oct. 2013

ware attack and its detection, specifically, from 240
days to more than 365 days. Conditions such as thesemake it difficult to obtain an accurate number of malware incidents. The literature indicates that at least
200 days are now needed to detect that something has
occurred. It can therefore be said that, at any point in
time, we just don’t know what is going on where.
Japan is the home of many globally known corporations that have a high probability of being targeted bymalware attacks, so it should be acknowledged that
attacks are occurring here and there on a daily basis.
Reports from Microsoft and elsewhere state that therisk of PC malware in Japan is not that high comparedto other countries, but I believe that it is only a matterof time before Japan too is affected by some globalwide incident.
Obviously, malware targets things of high value.
There are numerous cases of financial crimes andfraudulent uses of information in North America, andcase studies from South America reveal that the methods used in committing financial crimes can be quite
skillful and varied. Each country, region, and business field features particular methods of deception.
It appears that attack techniques that originate inSouth America and elsewhere arrive in Japan about
one or two years later. The good news here is that
understanding and analyzing incidents that are occurring in other regions in the world should enable us toanticipate and prevent to some extent security incidents in Japan. Case studies can help us makeadvanced preparations and take appropriate actions.
—Given this state of affairs, what specific activities
are you involved in?
Feature Articles(Academic organizations in Europe)
Collaborates on CSIRT creation andeducation/training(Japan’s national CSIRT)
Collaborates on alert information/response

TERENA (Europe)(Trans-European Research and
Education Networking
Association)(Academic organizations in Brazil)
Collaborates on bot/spam analysis
CAIS/RNP*(Brazil)

JPCERT/CC(Japan)JPCERT/CC(Japan)Web of Trust
Forum of Incident
Response andSecurity Teams

NTT-CERT(NTT I3)

Circle of Trust
NCA (Nippon
CSIRT Association)
Company
Company

ShadowServer(United States)(International organizationcollecting attack information)
Exchanges attack information

HoneynetProject(overseasorganizations)(Malware/honeypot research organization)
Exchanges honeypot techniques, malware
information, etc.

*The full name is Centro de Atendimento a Incidentes de Segurança / Rede Nacional de Ensino e Pesquisa (in Portuguese)

Fig. 2. Collaboration between NTT-CERT (NTT I3) and key CSIRTS inside/outside Japan.

I am involved in incident monitoring work in conjunction with NTT-CERT. The term “monitoringwork” may convey the idea of real-time incident
monitoring, but it also involves the important work of
releasing new information on which companies haveexperienced vulnerabilities and when, and of updating previously released, beneficial security information.
I also act as a liaison to other organizations involved
with information security.
In fact, in addition to issues involving attacks andvulnerabilities, my work spans the full breadth of the
IT industry. I must consider, for example, judicial andlegal matters, service providers, incident responders,
universities, other CSIRTs, vendor information, andendorsements.
My job is to uncover important information from acomplex web of data from which I need to determine
what type of information lies hidden and where, andwhat kind of impact that information might have. So
it’s not just a matter of keeping myself glued to ascreen 24 hours a day to collect information.
I also exchange information with organizations inother industries and with security activists in thesame industry via teleconferencing as the need arises.
In short, security work covers a wide range of activities—the day is over before I know it!
—You have participated in conferences and meetings
throughout the world. What are your prime objectives
here?
First of all, NTT became a member of the Forum of
Incident Response and Security Teams, or FIRST, theglobal consortium of CSIRTs, in 2005, which was
relatively early as a CSIRT in Japan (Fig. 2).
Being a member of FIRST helps NTT-CERT facilitate trustworthy interaction with other members andstrengthen all sorts of relationships, human or otherwise. It also ties in with incident response. For
example, there was a case in which we were able to
track an actual incident by receiving exceptional
cooperation from a CSIRT in another country. The
feeling is that we can get our hands on important facts
from reliable information sources in FIRST andreflect those facts in our response. There are also
cases in which incident reports from FIRST sources
are submitted prior to any problems occurring on ourside. All in all, becoming a FIRST member promotes
bidirectional problem solving.
I recently attended a number of conferences held in
Brazil, Argentina, Malta, and other countries either
for FIRST members or general participants(Photo 1).
I’ve also attended non-FIRST conferences on an
NTT Technical Review

Feature Articles—There are security risks in all regions of the world,with researchers there to pursue them. Therefore,
what are the benefits of working out of Silicon
Valley?

Photo 1. Participants at a FIRST meeting held in Thailand
June 16–21 (Lead Security Analyst Shin Adachi
is second from the left).

invitation basis, for example, those sponsored by the
National Cyber Security Center of The Netherlands(NCSC.NL). These conferences and meetings help
me to build up my knowledge and expand my network of contacts.
Of course, collecting information is an importanttask here, but raising one’s profile and obtaining thetrust of others is also an important activity. I also
accept invitations to lecture to increase my exposure
to the outside world. Speaking out in this way enables
me to disseminate the strengths of NTT I3 and NTTCERT. Through these activities, I hope to increase thenumber of colleagues I have in this field and to decideon what direction I should take.
Just recently, for example, NTT I3 applied for andreceived approval for membership in the Cloud Security Alliance (CSA), thereby joining ranks with wellknown companies such as AT&T and Verizon.
I believe that the CSA is the only global industry
body taking on both cloud computing and security. Its
activities include drafting white papers, so I believethat offering our help in such work is a good way forothers to learn about the highly talented staff, activities, and core competencies of NTT I3. I also thinkthat we can engage in effective PR through advertising and other activities targeting specialized fields.
Establishing a name will take several stages, but at
first, our aim is just to increase recognition of the
NTT I3 name and to signal to the industry that our top
priorities are cloud computing and security.
To spread the word about NTT I3’s capabilities, I
think the best approach is to combine such efforts
with other activities.

Vol. 11 No. 10 Oct. 2013

One advantage of establishing an R&D center inNorth America is that the time difference with Japan
can be put to good use. Specifically, in the case of
California, our colleagues in Japan can send us messages and inquiries before they leave for the day, andsince we are working while they are resting, we canreply to their messages by the early evening in ourtime. This means that they will receive our responses,
results, or progress reports first thing in the morning
the following day in Japan.
At the same time, working in just any location in
the United States is not necessarily beneficial. For
example, New York and Washington D.C., though
being the respective centers of American finance andgovernment and being located on the East Coast threehours ahead of California, are disadvantageous in thesense that software vendors tend to be located in
California.
Let me explain using a specific example, which
occurred some time ago. A new type of malware
began to infect computer systems on a certain weekend, and as dawn broke around the world, the malware infections spread from New Zealand and Australia to Japan and Europe, and eventually infectedcomputers on the East Coast of the United States. As
a result, one financial institution after another fell
victim to this malware and suffered damage. However, because major antivirus software vendors areconcentrated on the West Coast, no effective countermeasure to stem the effects of that damage could betaken until the start of the business day on Monday in
California. Such a situation would probably not occur
today, but there are still various reasons why time differences can sometimes be a major problem. It canalso be said that there are both good aspects and bad
aspects to having a concentration of vendors in the
California area, but understanding both sides also has
its benefits.
At present, I make an effort to get up before 4:00
AM Pacific Time in California every morning tocollect information on security matters affecting
financial and government institutions, but looking
forward, I would like to enhance and fortify the way
we cover East Coast problems.
At the risk of repeating myself, I’ll say that thepresent situation is such that I don’t know what isgoing on security-wise at all points around the world.
Feature Articles

But I do know that a new day begins with New Zealand and Australia—that will never change!
—What types of activities does NTT I3 intend to focus
on going forward?
As a new direction from a business point of view,
NTT I3 aims to support the datacenters and security
services of three NTT companies doing business inNorth America, namely, Dimension Data, NTT
America, and NTT DATA, Inc. Our mission is twofold: to protect the business operations of these companies and to determine which technologies areneeded to protect their customers.
Furthermore, to expand NTT’s cloud business, wemust keep two questions in mind: how do we protect
the security of the cloud business, and conversely,
how do we leverage the power of the cloud to protect
security?
The business of the NTT Group differs greatly
between Japan and North America in the services
provided to customers, the temperament and characteristics of customers, the business environment, andthe regulatory environment. This difference has a big
impact on security, the form of attacks referred to as
the “attack vector,” the way of dealing with vulnerabilities, and the incident response. I would like toapply the experience and achievements that we havebuilt up so far as a CSIRT to develop intellectual
property (IP) that can effectively support managed
security services.
To this end, I am beginning to exchange information on a face-to-face basis while also investigating
the specifics of how best to proceed from here on. I
am currently at the stage of establishing a firm foun-dation, and the key to this process is conducting interviews and meetings with the relevant players.
I also think that there is a wealth of talented, hardworking people in NTT R&D who are a true asset tothe company. In addition to being responsible andloyal professionals, their knowledge extends beyond
their specialized technologies to a broad range of
peripheral technologies, too. I believe it’s the duty of
NTT I3 to inform the outside world about the highlevel of R&D activities underway in the NTT laboratories.
If we remain silent about this, nothing will get off
the ground. Other Japanese firms may be involved insimilar activities, but I believe that NTT is at the forefront of security technologies. I would like the vastcapabilities of NTT to become well known.

Interviewee profile
Career highlights
Shin Adachi brings experience and expertise on
information security gained over many years to
NTT I3, as the Lead Security Analyst. He currently represents and serves NTT-CERT in theAmericas. In addition, he has spoken at, played
significant roles at, and/or contributed to, wellrecognized organizations such as FIRST, NIST
Cloud Computing Program, Liberty Alliance,
Kantara Initiative, APEC TEL eSecurity, Asia
PKI Consortium, and ITU-T. Currently, he isserving FIRST as CoChair of its Education Committee and as a senior member of its Program
Committee.

NTT Technical Review

Feature Articles: NTT I3—Seeking to Actively Develop
Global Cloud Services

Networking at NTT I3 andOutlook of SDN
Robert RaszukDistinguished Research Engineer,
NTT Innovation Institute, Inc.
Abstract

NTT I3 (NTT Innovation Institute, Inc.) has actively been carrying out
the tasks of developing cloud-related network technologies. Softwaredefined networking (SDN) in particular is considered to be a key technology for creating differentiation services for service providers such asNTT. Robert Raszuk, Distinguished Research Engineer at NTT I3, has a
lot of experience in achieving company visions of implementing networking and SDN. We asked him about the current status and prospects of SDN.
Keywords: global, cloud, SDN

Introduction
Distinguished Research Engineer Robert Raszuk,
who hails from Poland, has a wealth of experienceneeded to develop network solutions and achieve theInstitute’s vision of software-defined networking(SDN). In 1993, he went to the U.S. to study computer science, which led to his starting a business in
Poland. He completed his master’s degree in electrical engineering in 1995, as the growth of the Internet
was booming, and began his career as a network engineer. He has a wide range of experience in areas
involving network management to the developmentof technologies involving internal customers.
How will Mr. Raszuk’s experience at vendor companies be utilized at NTT, a service provider? He had
the choice of working at a number of world-famous
companies. However, he decided to join NTT, saying,“I admire Japanese culture, and believe that Japanesecompanies are No. 1.” We asked Distinguished
Research Engineer Raszuk about the state and outlook of SDN.
—What is a network and what is SDN?


There are a variety of definitions of a network. My
interpretation is, “A network is composed of datatransport and services.” Please think of it this way.
Right now, the concept of SDN differs from person
to person (Fig. 1). SDN is a technology for quickly
offering new, competitive services. I think that insteadof standing for “software,” the S in SDN really should
stand for “service.”
In general, there is no fixed way of thinking about
SDN, even among people in the industry. I can only
explain my concept by giving specific examples ofwhat I want to offer.
Some of my colleagues and I think that the value of
SDN lies in the focus on services. But there are also
developers who think that it is also important to build
and reinvent the transport part of the network.
A variety of groups such as I2RS (Interface to the
Routing System) and IRTF (Internet Research Task
Force) working groups (WGs), are working on standardizing SDN. There are also foundations such as
EWSDN (European Workshop on SDN) that develop
services and the ETSI (European Telecommunications Standards Institute) Network Functions Virtualization WG, which is focusing on software-based
NTT Technical Review

Feature Articles

Application layer
Business applications,network management system

Network configuration andmanagement interface
Control layer

Network-related
control (routing,forwarding, and ACL)

SDN control
software
Network control

Data plane control interface
Infrastructure layer
Packet forwarding
processing issued
by SDN control software

Network equipment

ACL: access control list

Source: Y. Nakajima, “Standardization Progress in Software Defined Networking/OpenFlow,”
NTT Technical Review, Vol. 11, No. 2, Feb. 2013.

Fig. 1. Overview of SDN architecture.

network functions and services.
So, there are many standardization efforts going on.
ONF (Open Networking Foundation) is working only
on the standardization of the OF (OpenFlow) portion,
which is the protocol for controlling the data planefrom the remote server.
Also, similar activities are being advanced by IETF
(Internet Engineering Task Force). They are standardizing definitions of methods of building APIs (application programming interfaces) into network equipment.
Because of these activities, it is difficult to completely follow what is happening in the SDN world.
There are activities being undertaken from various
perspectives, so understanding their real value as services will take a little more time.
There are many people in this industry who justfocus on services. However, if we don’t strengthendata transport, we can’t provide safe and secure netVol. 11 No. 10 Oct. 2013

works.
An example of a service is a virtual private network(VPN). With a VPN, Internet websites and portals canalso be provided. VPNs are therefore highly profitable services in the industry.
Using enterprise systems as an example, we see thatmany things are involved in the back office. For
example, solving different problems for document
management and server management and figuring
out how to manage them using a cloud-based infrastructure are issues of great concern right now. In
addition, cloud security is very important.
Instead of companies originally having their own
networks, more and more customers are outsourcing
their back office or using ready-made networks.
Almost all of these services are developed internally. The task of development is nothing special inparticular, since general programming languages areused. I think the challenge lies at the level ofFeature Articles

Network by SDN

Conventional network

Controller

Conventional router

BG

P

Transmission
equipment

ets

Pack

Fig. 2. BGP linkage.

innovation. What determines success is how to turnsomething from a concept into something real andcommercial.
The No. 1 purpose of network operators and service
operators is to increase revenue. In this industry,when one vendor develops a unique service, othervendors will quickly be able to provide similar features. Consequently, taking a year or two to conceive
a new service and to study and realize it will not bringsuccess to a business.
What is needed is the ability to conjecture whatcustomers will need and what they will demand, andquickly provide solutions. Customers want to pay as
little as possible for services that best match what
they need. Also, customers do not like to be locked
into just one service provider.
For mission critical applications, they generally
rely on several service providers. Even for services,
they do not wish to use a company’s proprietary technology, but prefer to be able to migrate easily fromone service provider to another. They also wish to
integrate service providers’ infrastructure and their
existing applications, especially the applications theycreated in-house.
In recognizing these conditions, I think the way toproceed is to first understand what the customer isrequesting, develop the service, and then design it for
the existing transport method.
For example, instead of using Internet services
from major vendors like Google for existing customers, I would rather offer services within NTT whose
quality is guaranteed by service level agreements(SLAs).


Customers are more interested in the services themselves than in how they are offered. I think we should
effectively leverage existing technologies. I don’t
think it’s desirable to offer competing technologies
especially for the transport part of networks.
By the way, a variety of work being developed by
IETF can be applied to SDN. Border Gateway Protocol (BGP) is becoming an actual service transport
protocol (Fig. 2).
—Mr. Raszuk, please share with us the specificresearch projects you are involved in.
I’m focusing on how to bring my knowledge ofrouting protocols into NTT I3 products. My first project at NTT was the invention of a service called BGP
Free Edge in 2011. This service removed the BGP
control plane from all the network edges and centralized the state plane while maintaining the data plane.
For example, we applied research to make use oftechnologies such as OpenFlow as applications.
BGP Free Edge is a technology that makes it possible to expand the footprint without additional costs
for service providers. For example, adding a new
POP (point of presence) can be implemented at anextremely low cost without purchasing expensive
routers or switches. This project is complete. We are
currently at the stage of carrying out trials with NTT
Communications.
Another project I’m involved in is AP (accesspoint) gateway automation. This project involves
speeding up connections to customers’ datacenters byusing a type of hotspot. I’m also actively participating
NTT Technical Review

Feature Articles

in IETF’s router-related activities.
I think new services can be produced as a result of
the in-house development of the control portion of
network controllers related to NTT I3’s own two BGP
protocol implementations. I’m tackling this rightnow. We have made it to the trial stage, but we are notquite there yet for the development release. However,I expect that the fruit of our labor from this projectwill give a boost to its productization. This projectwill be the first contribution of NTT I3 to NTT’s telecommunication companies.
—Why does NTT I3 need to be involved in SDN?
Right now, it looks like we are in an SDN bubble.
Small companies, not big companies, are beginningto participate. Opportunities to develop new X86based services are being created. There is a trend of
not only big network equipment vendors but also
many hardware manufacturers selling ODM (original
device manufacturer) boxes.
However, service providers, not vendors, are mostdominant in the area of the overall network becoming
software-defined. Also, even as service providers
have become involved in software recently, there
aren’t many companies that can develop their own
services as NTT I3 can. As a result of NTT I3’s
involvement in SDN, the NTT Group is more competitive and can provide customers with innovative
products and services.
—How is NTT I3 positioned in the IT industry with theresearch you are involved in?
I believe NTT I3 is trusted as a company that delivers quality services and delivers them securely.
Recently, I have been doing R&D on internal service development for NTT Communications. Because
I have been focusing on improving infrastructuresthat are associated with operators, my contribution to
the technology being developed that enhances theoverall lives of people in society has only been indirect, and I have not disclosed anything about thiswork to the public due to its proprietary nature. However, I know from experience that this is the firstresearch of its kind in the industry.
In the future, we can make life richer by building
robust systems, and contribute, for example, to the
medical field. I want to work on such projects thatwill make life better and deliver them to the world.
So I want to leverage NTT I3’s strength, which is its
ability to develop services that meet customers’
Vol. 11 No. 10 Oct. 2013

needs, in order to build up its competitiveness. Major
vendors tend to provide solutions for worldwide use.
I think we can strike a different path by using open
source software and open stack orchestration to create services with value and offer them in a timely
manner.
—Mr. Raszuk, you are living in Poland while working
for NTT I3, which is in Silicon Valley. To me, thisreflects a unique lifestyle. Is it natural?
There are various ways to work on a project. A concept is formed by having different ideas. After youcome up with the general idea, you create the basic
design called the system architecture, and then moveon to creating the component architecture. And thenyou move onto the actual tasks of development. You
start from the beginning with ideas of individuals,
and gradually move on to forming an organization.
You consider what personnel with what kinds ofskills are needed depending on the project, and build
a team. There are times when we use people who livein Silicon Valley, and there are times when people
from other countries participate.
I lived in Silicon Valley for a period of time before,
but then moved back to Poland for family reasons.
Since 2002 I have been working in Poland by telecommuting. Where a person lives is not an issue forengineers at companies like Cisco or Juniper. There
are people who communicate with one anotherthrough e-mail and videoconferences even though
they work on the same floor. By the way, when I was
living in Silicon Valley, my entire team was near Boston, and we communicated by telephone/video conference without any problems.
I’m able to do this because I maintain good relationships with team members. When we must holdimportant meetings for a project in person, engineersfrom around the world, including me, gather in Silicon Valley. I spend two to three weeks every quarterin San Mateo (Silicon Valley), or we organize meetings in Japan.
The key to achieving success on a project doesn’thinge on where a developer lives, but lies in gathering
outstanding human resources. The only challenge
might be in finding a suitable time for people in different locations to participate in a teleconference.
It’s very exciting to be able to create and develop
new services with my colleagues at NTT I3 in Silicon
Valley. Going forward, I want to improve these services by solving the challenges we face together withNTT Group companies around the world, include theFeature Articles

Group companies in North America. I’m looking
forward to collaborating with Dimension Data, which
is a system integrator. We can make a big impact on
the industry overall as a result of having common
goals.
Even now, I’m building quite a close relationshipwith the NTT laboratories. I’m thinking of further
building up and expanding this relationship byinvolving the research departments in different NTT
Group companies. To seriously carry the concept of
SDN further, we must focus more on the area ofdevelopment than on research when it comes to“R&D”.

Interviewee profile
Career highlights
Robert Raszuk began working for NTT in 2011.
His work currently focuses on defining new network architectures for innovative network services. He has over 20 years of experience working with large scale computer networks, including
Nations Bank (now Bank of America), Cisco Systems, and Juniper Networks. At NTT Innovation
Institute, Inc., he holds the position of Distinguished Research Engineer.

NTT Technical Review

Regular Articles

Load Modulation Applied toMagnetic Resonance Wireless Power
Transfer Technology and Its
Applications
Mamoru Akimoto and Masataka Iizuka
Abstract

The newly developed magnetic resonance wireless power transfer technology is being intensively
researched since it is easier to use than conventional technology and has potential applications in various
fields. In this article, we first provide an overview of similar techniques; then we introduce a method ofusing this power transfer technology that adopts load modulation in order to increase its range ofapplicability. We also describe an example of how this method can be used to reduce the effort needed
for manhole maintenance, and we present evaluation results regarding the optimal placement of thetransmitter and receiver coils in the example application.
Keywords: wireless power transfer, magnetic resonance, load modulation

1. Introduction––magnetic resonancewireless power transfer
In 2007, a new wireless power transfer technology
was developed at the Massachusetts Institute of Technology (MIT) [1]. This technology is referred to as
magnetic resonance*1 and differs from conventional
wireless power transfer technologies such as radio
frequency radiation and electromagnetic induction,
as shown in Fig. 1 [2]. One example of radio frequency radiation technology is a solar power satellite(SPS)*2, where energy is changed from an electricalcurrent to an electric wave and transmitted between
antennas. This method is applied when transmission
distances are comparatively long. By contrast, electromagnetic induction is used in, for example, chargers for electric toothbrushes and electric shavers.
Another name for this technology is the non-contact
method. As the name suggests, electrical power istransmitted when one of a pair of coils is brought into
close proximity with the other coil. Current is passed
through the transmitter coil, and magnetic flux istransmitted to the receiver coil where a current is
induced. In 2010, Qi, an international inductive
power standard (Ver. 1.0) for up to 5 W, was established, and devices based on this standard have since
been commercialized [3]. In comparison to these conventional technologies, magnetic resonance has intermediate characteristics, as shown in Fig. 1. Furthermore, even if the direction or position of the opposite
coil is not aligned perfectly, the degradation in thetransmission efficiency is slight, and in this sense it iseasy to use. Research and development on this technology is being actively pursued over a wide range offields such as automotive, consumer electronics, andmedical fields, and new applications are expected to
be introduced.
*1	 This technology is referred to by many names, including magnetic resonance and magnetic coupling. For consistency, we use theterm magnetic resonance in this article.
*2 Solar power satellite (SPS): Research is being conducted on generating electrical power from sunlight in space and transferring
the electrical power to terrestrial power stations using microwaves regardless of the time of day or the weather conditions.

NTT Technical Review

Regular Articles

Distance that power is transferred

10 m

1m

Radio-frequency emission
Efficiency 1% or less

10 cm

Magnetic resonance
Efficiency 40%–60%
Electric field resonance

1 cm
Electromagnetic induction
Efficiency 70%–90%
1 mm

0.1

1

10

100

1000

Transmission power (W)*Since the efficiency rating includes the power source, the efficiency rating for the entire transmission system is given.

Fig. 1. Comparison of wireless power transfer methods.
(http://bwf-yrp.net/menu-03-06-01.html)

The principle of magnetic resonance power transfer
is often explained by using the example of two distanttuning forks, where when one is struck the other resonates and begins to generate sound. A more precise
explanation is that the quality factors (Q factors) of
the transmitter and receiver coils are increased, andby matching the resonant frequencies of both coils,
the electromagnetic coupling between the coils is
strengthened, and electrical power is transferred. Thistransmission principle is basically the same as that for
the electromagnetic induction mentioned earlier. The
transmission efficiency of both methods is given by
the product of the coil Q factor and the coupling coefficient. The electromagnetic induction approachincreases the coupling coefficient by bringing thecoils into close proximity, and the magnetic resonance approach increases the coil resonance characteristics, i.e., the Q factor.
2. Adopting load modulation
The NTT Access Network Service Systems Laboratories is engaging in preparations for plans to further improve the utilization of various anticipatedapplications for magnetic resonance power transfer
technology. One such application involves adopting
load modulation [4]. Load modulation is a technology
used in conducting communications. An example ispassive radio frequency identification (RFID) tags,
which are already widely used. A reader-writer transmits a carrier wave, and in response, the internal
Vol. 11 No. 10 Oct. 2013

impedance in the RFID tag changes depending on the
response data and generates a reflected wave, whichis then received by the reader-writer. A schematic
illustration of a magnetic resonance power transfer
setup that adopts load modulation is shown in Fig. 2.
In the figure, the receiver is connected to a sensor, andelectrical power that is transmitted from the transmitter coil drives the receiver circuit and sensor. Conversely, on the receiver side, the load impedance
inside the receiver changes depending on the sensor
information, and the resonant state between the transmitter and receiver coils changes. This change manifests a change in the reflection characteristics of thetransmitter coil input port, and through detection anddemodulation, information is extracted as a signal.
With this construction, the use of power sources suchas commercial power supplies and batteries is unnecessary on the receiver side (maintenance-free). It isthen possible for the receiver side to draw power off
the power supplied to the sensor and obtain sensor
information.
3. Coupling properties of arbitrarily set coils
and application example of manhole
maintenance
As mentioned earlier, various applications of themagnetic resonance wireless power transfer technology are expected since it is easier to use than conventional power transfer technology. The transmitter andreceiver coils do not need to be positioned facingRegular Articles

Power source is not used because the receiver side receives
electrical power from the transmitter coil.

Information
Transmitter coil

Receiver coil
Load modulation

SensorElectrical power

Modulator etc.

ReceiverController etc.

Demodulator
etc.

Power supply

Transmitter

By controlling the impedance to the receiver coil, the resonancestates of both coils are changed. The transmitter coil side
receives information by detecting this change.

Fig. 2. Overview of magnetic resonance wireless power transfer method with load modulation.

Z

each other and therefore, the transmission efficiency
properties of an arbitrarily arranged coil configuration need to be ascertained. On the basis of coupling
mode theory, we show the transmission efficiency ofmagnetic resonance wireless power transfer using
performance index U in the following equation [1].

α

ds2

Q1 Q2
M
L1 L 2(1)

Here, Q1 and Q2 are the respective Q factors forcoils C1 and C2, L1 and L2 are the respective selfinductance values for coils C1 and C2, and M is themutual inductance between coils C1 and C2. From
Eq. (1), if the Q factors of the coils and self-inductance are assumed to be fixed, the transmission efficiency representing the performance index U depends
on mutual inductance M. The following equation
expresses mutual inductance M when it is an ideal
conductor based on Neumann’s formula (µ0: magnetic permeability in free space)
M=

µ0
4π

∫ ∫

C1 C2

cosθ
ds1ds2r(2)

On the basis of Eq. (2), using the loop coil pair in
Fig. 3, we calculated the mutual inductance, which isplotted in Figs. 4 and 5. It is evident in Fig. 4 that themutual conductance is high for the intermediate
range of 45˚–70˚ as the angular position of coil C2, Θ,
when the angle of inclination of coil C2, α, is 90˚.
Furthermore, we can see in Fig. 5 that the maximum
value of the mutual inductance, M max, does notchange significantly (1 => 0.75) even if the angular


C1

r
θ

C2

U=

Θ

X

ds1

Y

α : Angle formed between central axis ofcoil C2 and Z axis direction
Θ: Angle formed between the direction
from the origin to the center of coil C2
and the Z axis
θ : Angle formed between ds1 and ds2
r : Distance between ds1 and ds2

Fig. 3. Loop-coil pair.

position of coil C2, Θ, is changed; that αmax when M= Mmax depends on Θ; and that αmax changes over therange of 0–180˚. Keeping in mind the above characteristics, we describe the maintenance of manholes as
an application example of wireless power transfer
adopting load modulation [5].
There are approximately 680,000 communications
related manholes throughout the country. Amongthese, 80% have been in service for more than 30
years [6] and are deteriorating. Furthermore, inspecting the interiors of manholes requires much effort.
Permission must be obtained in advance to access theroad, and arrangements such as for traffic control andmanhole ventilation must be made prior to inspection. Accordingly, studies have been done on optimizing the maintenance work using wireless technology
NTT Technical Review

Regular Articles

Normalized mutual inductance: M

1

α=0 degrees
α=90 degrees
α=Θ

0.75

0.5

0.25

0

0

30

60

90

Θ (degrees)

1.00

180

0.75

135

0.50

90

0.25

45

0.00

0

15

30

45
Θ (degrees)

60

75

90

α when M = Mmax: αmax (degrees)

Maximum value of normalized
mutual inductance: Mmax

Fig. 4. Dependence of normalized mutual inductance on Θ.

0Fig. 5. Dependence of Mmax and αmax on Θ.

[7], [8]. In this application example, a receiver coiland sensors used in structure diagnosis such as astrain gauge and accelerometer are installed inside
the manhole. Load modulation is used to communicate the sensor information, and magnetic resonancepower transfer technology is used to supply electricity to the sensors. This makes it possible to tackle thegoal of reducing the amount of maintenance work in
manholes and also that of strengthening the cost competitiveness and improving the reliability of the transmission equipment.
Here, we investigate a specific configuration method for the receiver coil based on the mutual inductance characteristics in Eq. (2) for this type of application. The construction of a general manhole isclassified into the cover, the chamber, and the neckthat connects the chamber and surface (Fig. 6). In
some cases, the chamber is constructed of concretethat contains a rebar grid; because the rebar can affectVol. 11 No. 10 Oct. 2013

the magnetic resonance wireless power transfer, thereceiver coil is placed in the neck. In contrast, thecover is made from cast iron, which has a large effecton this system. Therefore, the transmitter coil is positioned level to the ground on the periphery of thecover to avoid the upper part of the cover and to simplify the maintenance work.
We calculated the mutual inductance based on theabove conditions; the results are shown in Fig. 7.
These results show that when the receiver coil is positioned in the neck at 90˚ (vertical), the range of theangle of the transmitter coil placement (angle atwhich the transmitter coil is installed) to achieve highmutual inductance is extremely wide. Next, we show
the results when the required mutual inductance ofthe system is tentatively 0.5, and the range of anglesof the transmitter coil location that exceeds thisrequirement is calculated from the depth of thereceiver coil as a parameter (Fig. 8). From theseRegular Articles

Maintenance worker
Cover
Surface (road)

Transmitter coilElectrical
power

Neck
SensorSensorReceiver coil

Chamber
ManholeFig. 6. Manhole maintenance setup.

Normalized mutual inductance: M

1

ΦTop view

0.75

α

0.5

70 cm
Side view

70 cm
0.25

0

0 degrees
45 degrees
90 degrees
0

30

60

90

120

150

Radius of manhole neck: 35 cm
Coil radius: 25 cm

180

Angle Φ of transmitter coil location (degrees)

Range of transmitter coil angles that satisfy
the requirements (M>=0.5), (degrees)Fig. 7. Dependence of normalized mutual inductance on angle of the transmitter coil location.

180

α =
0 degrees
30 degrees
45 degrees
60 degrees
90 degrees

150
120
90
60
30
0

40

50

60
70
80
Depth of receiver coil (cm)

90

100

Fig. 8. Range of transmitter coil angles that satisfy the requirements.



NTT Technical Review

Regular Articles

results as well, for a practical receiver coil depth (afew tens of centimeters), when the receiver coil is
installed in the neck at 90˚, we find that the range ofangles of the transmitter coil placement that satisfied
the standard value (M >= 0.5) is extremely wide.
4. Future development
In this article, we summarized wireless powertransfer technology and introduced the magnetic resonance method that has been extensively researchedand developed in recent years. We also described themagnetic resonance method adopting load modulation, a method for improving applicability, and an
application example. In terms of practical application, various problems exist such as achieving highefficiency of the coils themselves, achieving highefficiency of the entire system including the load system, and determining how to adjust and alleviate thereduction in efficiency due to variations in impedance
caused by the influence from the surrounding environment. The Wireless Power Transfer Working
Group of the Broadband Wireless Forum is actively
discussing standardization with a focus on wirelesspower transfer including magnetic resonance,cooperation with other countries, and legislation andregulation related to radio laws and human safety.
Over the past few years, extensive discussions andMamoru Akimoto

Senior Research Engineer, Wireless Access
Systems Project, NTT Access Network Service
Systems Laboratories.
He received the B.E. and M.E. degrees from
Tsukuba University, Ibaraki, in 1989 and 1991,
respectively. He joined NTT Radio Communication Systems Laboratories (now NTT AccessNetwork Service Systems Laboratories) in 1991.
He is currently engaged in R&D of wide-area
wireless access systems. He is a member of theInstitute of Electronics, Information and Communication Engineers (IEICE).

Vol. 11 No. 10 Oct. 2013

investigations have taken place from various viewpoints, and we anticipate that the day will be upon us
soon when products and services employ this technology.
References
[1]
[2]
[3]
[4]
[5]
[6]

[7]

[8]

A. Kurs, A. Karalis, R. Moffatt, J. D. Joannopoulos, P. Fisher, and M.
Soljacic, “Wireless Power Transfer via Strongly Coupled Magnetic
Resonances,” Science, Vol. 317, No. 5834, pp. 83–86, 2007.
Broadband Wireless Forum. http://bwf-yrp.net/english/
T. Kanai, Y. Kanai, and N. Nomura, “Wireless-charging Mobile Terminal by the WPC System: “Just Set It Down to Charge,” NTT
DOCOMO Technical Journal, Vol. 12, No. 4, 2011.
T. Maruyama, T. Shimizu, M. Akimoto, and K. Maruta, “Data Transmission Using Original Coils in Resonant Wireless Power Transmission,” IEICE Trans. Com. Vol. E94-B, No. 11, pp. 3172–3174, 2011.
M. Akimoto and M. Iizuka, “Mutual Inductance Characteristics of
Misalignment Coils and the Application on WPT,” Proc. of the IEICE
Gen. Conf. 2013, B-1-17, Gifu, Japan, March 2013 (in Japanese).
F. Sugino, “R&D Trends in Communications Infrastructure to
Achieve Safe and Secure Access Networks,” NTT Technical Review,Vol. 11, No. 6, 2013.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr2013
06fa2.html
H. Tsuboi, H. Yoshioka, A. Ando, and H. Nakamura, “Study of aRadio System that Can Amass Information about Manholes from a
Moving Vehicle,” Proc. of the IEICE Gen. Conf. 2012, B-5-39,
Okayama, Japan, March 2012 (in Japanese).
A. Ando, H. Tsuboi, and H. Nakamura, “Measurements of Received
Signal Levels in Manhole Using Electromagnetically Coupled Manhole Cover Antennas,” Proc. of the IEICE Gen. Conf. 2012, B-1-55,
Okayama, Japan, March 2012 (in Japanese).

Masataka Iizuka

Senior Research Engineer, Supervisor, Wireless Access Systems Project, NTT Access Network Service Systems Laboratories.
He received the B.E. and M.E. degrees fromTohoku University, Miyagi, in 1988 and 1990,
respectively. In 1990, he joined NTT Radio Communications Systems Laboratories (now NTT
Access Network Service Systems Laboratories)and studied radio channel control techniques for
personal communications systems. From 1997 to
2006, his research interests were in radio access
control schemes for high speed wireless LAN.
After completing the commercial developmentof a wireless LAN system based on IEEE
802.11a, he was engaged in the promotion of the
Next-Generation Network system. He is currently with NTT Access Network Service Systems Laboratories, responsible for R&D ofwide-area wireless access systems. He is a member of IEICE.

Regular Articles

Reducing Electric Power
Consumption for Air Conditioning by
Improving Temperature Distribution
in Telecom Equipment Rooms
Masato Maruyama, Akiko Takahashi, Hiroya Yajima,
Akira Takeuchi, Nobuhiko Yamashita,
Morihiko Matsumoto, and Kimihiro Tajima
Abstract

This article presents the results of an electric-power-reduction experiment that was conducted incollaboration with the NTT WEST Kochi branch. One effective way to reduce the amount of electric
power required for air conditioning in a telecom equipment room (TER) is to eliminate hot spots. In theexperiment, the causes of two hot spots generated in the existing TER were analyzed, and various heatcontrol methods were implemented to eliminate them. Then the effects these methods had on reducing
the temperature and on reducing the required air conditioning power were evaluated.
Keywords: telecom equipment room, air conditioning, electric power reduction

1. Introduction
The suspension of nuclear power plant operations
after the catastrophic disaster in northeastern Japan in
March 2011 caused an electric power shortage during
the subsequent summer and winter in Japan. It has
also led to an increase in the price of electric power.
The NTT Group consumes 8 billion kWh of electricity per year (corresponding to 1% of gross electric
power consumption in Japan) in order to provide its
telecommunication services. Consequently, any
reduction in the power supply is an extremely important issue from the viewpoint of corporate social
responsibility and business continuity. The NTT
group has therefore been implementing various measures to remedy this situation.
One of these measures involves reducing theamount of power required for air conditioning in telecommunication equipment rooms (TERs). TERs arefound in NTT buildings throughout Japan and containvarious kinds of information and communications
technology (ICT) equipment such as routers and servers, as well as the power supply units and air conditioning units required by them. Most TERs utilize araised-floor system so that cold air from the air conditioning units can circulate throughout the floor
space in order to cool the ICT equipment. The hot
exhaust from the ICT equipment is then returned tothe air conditioning units located near the ceiling.
However, in many TERs, a variety of factors may
result in the formation of hot spots, where the temperature is higher than in other parts of the room. In
this situation, the air conditioning outputs have to be
set higher in order to prevent failure of the ICT equipment. However, this also causes an increase in electric power consumption. If such hot spots can beeliminated, the power consumption could be reduced
by lowering the air conditioning output.
NTT Energy and Environment Systems Laboratories has been researching various methods to cope
NTT Technical Review

Regular Articles

Air conditioning units

Temp. (°C)
31
29
27
25

Hot spot 1

23
21

29.6 °C

Hot spot 2

31.4 °C
Racks for ICT equipment

Air conditioning units

Fig. 1. Temperature distribution map of TER.

with these sorts of heat problems in TERs [1]–[3].
This article presents the results of a power-reduction
experiment that was conducted in collaboration with
the NTT WEST Kochi branch. In this experiment,
various methods to control heat were implemented
and compared. As a result, air conditioning powerreduction effects were achieved in conjunction with
reductions in hot spots.
2. Visualization of TER in NTT
Kochi-Naka building
The TER in the NTT Kochi-Naka building where
the experiment was conducted covers an area of
430 m2 and contains 100 racks for ICT equipment
and seven air conditioning units. It also houses thepower and temperature visualization system thatNTT Energy and Environment Systems Laboratories
developed and installed. This system monitors thevalue of electric power that each piece of ICT equipment consumes and the temperature around it, anddisplays the data as a two-dimensional distribution
map or time-domain graph. The sensors that record
the data are installed in each rack and air conditioningunit.
The temperature distribution map for the entire
room is shown in Fig. 1. The color of each balloon in
the figure signifies the temperature at that point. As
shown in the figure, there were originally two hot
spots in the room. One (hot spot 1) was found near theVol. 11 No. 10 Oct. 2013

center of the room on the left-hand side, where themaximum temperature recorded was 31.4°C. The
other (hot spot 2) was located near the center on theright-hand side, and the maximum temperaturerecorded there was 29.6°C.
We investigated the causes of the elevated temperatures at these two hot spots, introduced some modifications in an attempt to overcome the overheatingproblem, and evaluated the effectiveness of thesesolutions. We carried out this work with the cooperation of the NTT WEST Kochi branch, NTT WESTSHIKOKU, NTT NEOMEIT Shikoku branch, and
NTT FACILITIES KANSAI.
3. Solutions for hot spots in TERs
3.1 Solution 1: Airflow control panels
Our investigations revealed that hot spot 1 had twocauses. One was the rear-to-front layout in which theexhaust port of one ICT unit faces the intake port ofanother. As a result, the high-temperature exhaustfrom the ICT equipment (emitter equipment) flows
directly into the intake port of adjacent units (affected
equipment), thereby raising the intake temperature(Fig. 2(a)). To avoid this situation, ICT equipment
has in recent years been arranged to form a cold aisle(hot aisle) across which intake ports (exhaust ports)
face each other when new TERs are constructed.
However, in TERs that were constructed before thisarrangement was introduced and that are still inRegular Articles

operation today, the rear-to-front layout is still common.
To improve this state of affairs, we added airflow
control panels to the exhaust port of the emitter
equipment, so that the exhaust was now directed

upwards (Fig. 2(b)). As a result, the direct effect of
the high-temperature exhaust on the affected equipment was eliminated without needing to alter theiractual layout. The shape of the panel was designedwith the help of airflow computer simulations so that
other equipment nearby would not be affected.
3.2 Solution 2: Blank panels
The other cause of elevated temperatures at hot spot
1 was the hot air exhaust emitted from the top face ofthe equipment. When ICT equipment has an exhaust
port on its top face, bottom face, right side or left side,
the exhaust from that port enters the cold aisle as wellas the hot aisle and raises the temperature (Fig. 3).
To correct this, we installed blank panels so that the
hot exhaust only flowed into the hot aisle (Fig. 4).

Outlet port Inlet port ofof emitting affected
equipment equipment(a) Before (rear-to-front layout)(b) After

Fig. 2 Airflow control panel for rear-to-front layout.

Hot aisle

3.3 S
 olution 3: Adjustment of air quantity taken
in by forced-air cooling racks
While investigating hot spot 2, we found that theCold aisle

Hot aisle
Rear-outlet equipment(good)

Side-outlet equipment(bad)

Rear-outlet equipment(good)

Top-outlet equipment(bad)Fig. 3. Example of hot air inflow into the cold aisle.

Inlet port
Inlet port

Blank panels(a) Before(b) After

Fig. 4. Blank panels installed to block hot air inflow into the cold aisle.



NTT Technical Review

Regular Articles(a) Exterior(b) Rack fansFig. 5. Forced-air cooling rack.

Air conditioning units

Air conditioning units
Temp. (°C)
31
29
27
25
23
21

29.6 °C

28.9 °C

27.9 °C

28.5 °C

Air conditioning units

Air conditioning units(a) After implementing solutions 1 and 2(b) After implementing solutions 1, 2, and 3

Forced-air
cooling rack

Fig. 6. Temperature reductions after implementing solutions.

circulation of cold air under the raised floor was inadequate in that area. One of the reasons for this was
suspected to be excessive cooling of the forced-air
cooling racks, 30 of which were installed in thatparticular room. A forced-air cooling rack is a type ofclosed rack that takes in cold air from under the raised
floor using fans, and then uses this cold air to cool the
ICT equipment (Fig. 5). It is often used for equipmentthat produces a lot of heat because it can supply large
amounts of cold air for cooling purposes. Generally,
the quantity of air that the rack takes in is set in thedesign phase and is not changed after that. As a result,the quantity of air that the rack takes in may be considerably larger than the amount of cooling the equipment in the rack actually requires. Massive overconsumption by a number of racks may, therefore, cause
Vol. 11 No. 10 Oct. 2013a lack of cold air under the raised floor.
We adjusted the quantity of air taken in by the racks
so that the inside temperature was maintained at the
optimum level. This was achieved by measuring thetemperature of the exhaust from the upper surface ofeach rack and then minimizing the number of fansrunning so that the temperature of the exhaust did notexceed the steady-state value determined in advance.
4. Some solutions to optimize temperatureand prevent hot spots
The temperature distribution throughout the room
after introducing the airflow control panels and theblank panels is shown in Fig. 6(a). A comparison of
the results with the image in Fig. 1, which shows theTotal electric power consumptionof air conditioning units (kW)Regular Articles

35

Original setting
Raised setting

30
25
28.7 kW20

25.5 kW
15

10

15

20

25

Outdoor temperature (°C)

Fig. 7. Air conditioning electric power consumption versus outdoor temperature.

temperature distribution before alteration, shows thatthe temperature at hot spot 1 was significantly
reduced. The maximum temperature fell from 31.4°C
to 28.9°C. By contrast, the temperature at hot spot 2
did not change significantly. This is because the solutions implemented only have a localized effect.
The temperature distribution after adjusting thequantity of air taken in by the forced-air coolingracks, in addition to the two solutions implemented
earlier, is shown in Fig. 6(b). Comparing Fig. 6(a)with Fig. 6(b) shows that the temperature of most of
the racks (except the forced-air cooling racks) was
reduced as a result. The maximum temperature of hot
spot 2 fell from 29.6°C to 27.9°C, and that of hot spot
1 dropped to 28.5°C.
5. Electric power savings achieved by
reducing air conditioning
Adopting the three solutions described above
reduced the maximum temperature of the room to
28.5°C. This meant that it was now possible to reduce
the amount of air conditioning needed, so we altered
the settings of all the air conditioning units andobserved the change in electric power consumption.
The temperature setting for the return air entering the
air conditioning units was raised by 1.5°C in order toraise the maximum temperature of the room to 30°C(the usual temperature maintained in TERs).
The relationship between the total amount of electricity used by all the air conditioning units in theroom and the outdoor temperature is shown in Fig. 7.
The blue and red points show the power consumption
levels measured when the room temperature was at its

original setting and at the raised setting, respectively.
Air conditioning power consumption decreased by
3.2 kW (11%) after raising the temperature setting by
1.5°C (at an outdoor temperature of 20°C). Thismeans that the cost of air conditioning could be
reduced by 300,000–400,000 yen every year.
6. Conclusion
As a result of this joint experiment carried out inconjunction with the NTT WEST Kochi branch, thestatus of hot spots in the TER inside the Kochi-Nakabuilding was improved significantly, and the air conditioning requirements were reduced. Changing thetemperature settings by 1.5°C achieved an 11%
reduction in air conditioning power consumption
when the outdoor temperature was 20°C. We are continuing to research and improve these power-saving
techniques so that they can be adopted more widely,in cooperation with each company within the NTT
Group.
References
[1]

[2]
[3]

M. Maruyama, R. Nakamura, K. Matsuo, and T. Tominaga, “Estimation of Power Savings of Air Conditioning by Closing Cable Holeunder Server Racks,” Proc. of the Society Conference of IEICE, BS5-5, Hokkaido, Japan, 2011 (in Japanese).
K. Matsuo and T. Tominaga, “Method of Straightening Out Air Current When Installing ICT Equipment in Cabinets,” Proc. of the Society
Conference of IEICE, C-6-5, Toyama, Japan, 2012 (in Japanese).
A. Takahashi, H. Yajima, M. Maruyama, A. Takeuchi, N. Yamashita,
and M. Matsumoto, “Countermeasures against Heat in Telecom
Equipment Rooms and Reducing Electric Power Consumption of Air
Conditioning,” Proc. of the General Conference of IEICE, C-6-5,
Gifu, Japan, 2013 (in Japanese).

NTT Technical Review

Regular Articles

Masato Maruyama

Research Engineer, EMC Technology Group,
Energy Systems Project, NTT Energy and Environment Systems Laboratories.
He received the B.E. and M.E. degrees in electronics engineering from the University of Electro-Communications, Tokyo, in 2001 and 2003,
respectively. He joined NTT Energy and Environment Systems Laboratories in 2003 and has
been engaged in studies on stability of DC power
supply systems and optimization of air conditioning for telecom equipment rooms.

Akiko Takahashi

Researcher, Energy Supply Systems Development Project, First Promotion Project, NTT
Energy and Environment Systems Laboratories.
She received the B.E. and M.E. degrees inelectrical engineering from Tokyo University ofAgriculture and Technology in 2008 and 2010,
respectively. She joined NTT FACILITIES, INC.
in 2010 and engaged in maintenance of powersystems for telecommunication systems. Since
2012, she has been researching power reductionin telecom equipment rooms at NTT Energy andEnvironment Systems Laboratories.

Hiroya Yajima

Researcher, Energy Supply Systems Development Project, First Promotion Project, NTT
Energy and Environment Systems Laboratories.
He received the B.E. and M.E. degrees in electrical engineering from Utsunomiya University,
Tochigi, in 2005 and 2007, respectively. He
joined NTT FACILITIES, INC. in 2007 andengaged in development of Uninterruptible
Power Supplies. He moved to NTT Energy andEnvironment Systems Laboratories in 2011 andis currently researching a DC power supply system for telecommunication systems.

Akira Takeuchi

Senior Research Engineer, Energy Supply
Systems Development Project, First Promotion
Project, NTT Energy and Environment Systems
Laboratories.
He received the B.E. and M.E. degrees in electronics engineering from Kyushu University,
Fukuoka, in 1990 and 1992, respectively. He
joined NTT Interdisciplinary Research Laboratories (now NTT Energy and Environment Systems
Laboratories) in 1992. His research interests are
power converters, energy control technologies,
and optimization techniques. He is a member ofIEEE and the Institute of Electronics, Information and Communication Engineers (IEICE).

Vol. 11 No. 10 Oct. 2013

Nobuhiko Yamashita

Senior Research Engineer, Supervisor, Energy
Supply Systems Development Project, First Promotion Project, NTT Energy and Environment
Systems Laboratories.
He received the B.E. degree from Kyushu
Institute of Technology, Fukuoka, in 1987. He
joined NTT Electrical Communications Laboratories in 1987, and engaged in studies on highspeed power semiconductor devices and circuits
for DC–DC converters. After working for
ENNET Corporation and NTT FACILITIES,
INC., he joined NTT Energy and Environment
Systems Laboratories. He is currently developing
power supply systems for telecommunication
systems. He is a member of IEEE, the Institutionof Electrical Engineers, and IEICE. He received
the IEICE Academic Encouragement Award in1995 and the IEICE Communications Society
Distinguished Contributions Award in 2004.

Morihiko Matsumoto

Director of Energy Supply Systems Development Project, First Promotion Project, NTT
Energy and Environment Systems Laboratories.
He received the B.E., M.E., and Ph.D. degrees
from Tokyo Institute of Technology in 1988,
1990, and 1996, respectively. In 1990, he joined
NTT Applied Electronics Laboratories, where heengaged in studies on electrolytes of solid lithium batteries. After that, he developed electromagnetic wave absorbers and noise filters for use
in buildings and devices. He was also involved inmaintaining access network equipment and managing FTTH operations at NTT EAST. He iscurrently developing power supply and air conditioning systems for telecommunication systems.
He moved to NTT Energy and Environment
Systems Laboratories in 2011. He received the
4th International Union of Materials ResearchSocieties (IUMRS-ICA-97) Young ResearcherAward in 1997.

Kimihiro Tajima

Executive Manager, EMC Center, NTT
Advanced Technology Corporation.
He received the B.E. and M.E. degrees fromthe Department of Electronics at Kumamoto
University in 1986 and 1989, respectively. He
joined NTT Telecommunications Networks
Laboratories in 1989. He has been engaged instudies on optical-scheme-based measuringmethods in the electromagnetic compatibility(EMC) field and the development of mobile communication systems using infrared rays for EMC.
He moved to the EMC Center in 2013 and is currently involved in developing EMC solutions at
NTT Advanced Technology Corporation. He is
the secretary of the Japanese National Committee of CISPR (International Special Committeeon Radio Interference) Group A. He is a memberof IEEE and IEICE.

Global Standardization Activities

IEEE 802.11 Wireless LAN
Standardization Trends
Yusuke Asai, Yasuhiko Inoue, and Yasushi Takatori
Abstract

This article gives an overview of the Institute of Electrical and Electronics Engineers (IEEE) 802.11
Working Group (WG), which creates standards for wireless local area networks (LANs). We include
information on its relationships with external organizations, its standardization processes, and a list of
existing amendments to IEEE 802.11. Some of the latest trends in standardization are also introduced,
including IEEE 802.11ac, which is an amendment of the IEEE 802.11 standard to increase systemthroughput, and we explain the status of the High Efficiency WLAN Study Group (HEW SG), which has
begun standardization work to enhance transmission efficiency in high-density deployment of accesspoints and stations.
Keywords: IEEE 802.11, wireless LAN, multi-user MIMO

1. Overview of 802.11 WG

2. 802.11 WG standardization process

The Institute of Electrical and Electronics Engineers (IEEE) 802 Committee (from here on, “802Commitee”) is the organization that develops andmaintains standards for the physical and data-linklayers of transmission media for wired and wirelessnetworks. The 802.11 Working Group (WG) wasestablished within this organization in 1990 to create
standards for implementing wireless Ethernet. The
802.11 WG carries out development by cooperating
widely with standardization and industry organizations within and outside of the 802 subcommittees(Fig. 1). In particular, the Wi-Fi Alliance, which certifies interoperability among IEEE 802.11 wireless
local area network (LAN) devices, has played a largerole in the explosive spread of wireless LAN products[1]. As shown in Fig. 2, since the initial 802.11 standard was published, it has been extended with many
amendments that address the increasing speed andfunctionality, which include faster transmission
speeds (802.11a/b/g/n/ac/ad), priority control basedon type of traffic (802.11e/aa/ae), security improvements (802.11i/w), extended wireless LAN functionality (802.11F/h/k/r/s/u/v/z), and support for frequencies used in different countries (802.11d/j/y).

The standardization process adhered to in the802.11 WG is as follows. First, the needs for a new
standard for future wireless LAN systems are discussed in the Wireless LAN Next-Generation Standing Committee (WNG SC). Here, the need for a new
standard is proposed, and if this is approved by the
New Standard Committee (NesCom) in the IEEE
Standards Association (IEEE-SA), which is a higherlevel organization of the 802.11 WG, a study group(SG) is established. In the SG, a prospectus is createdthat outlines the goals of the new standard to be created, including the scope, marketability and feasibility of the study. After the prospectus is approved, atask group (TG) is established, and concrete discussion toward creating the specification begins.
The TG decides, to some extent at its own discretion, how the work will proceed. The following is one
example. First, documents summarizing the functional requirements to achieve the goals of the activity and the evaluation methodology for each technicalproposal are created. Then, technical proposals thatsatisfy these conditions are invited. If there are multiple competing proposals, the technology to be used
is narrowed-down through voting or other means.
After a single technical specification has beenNTT Technical Review

Global Standardization Activities

802 Executive Committee
Wired WGs
802.1:
High-layer
LAN protocols

Wireless WGs

802.3:
Ethernet

802.16: WMAN
802.15: WPAN
(Wireless personal (Wireless metropolitan
area networks)
area networks)
Cooperates to ensurecoexistence of WLAN
and WPAN

Cooperates on bridgefunction extensions
for transmitting video
in the home

802.21: MIHS
(Media independent
handover services)802.22: WRAN
(Wireless regional area networks)

Studies handover between
IEEE802 standards
802.19: Wireless coexistenceStudies shared frequency use

802.11: WLAN
(Wireless local
area networks)

Studies IMT-Advanced
802.18: Regulatory rules
802.24: Smart grid

TAG*

Studies application of WLAN to smart gridIEEE 802 Standards Committees

Consolidate liaison relationships with external organizations, periodically exchange opinions, and cooperate in studies
ISO JTC1/SC6

Wi-Fi Alliance
Certifies interconnectivity
among wireless LAN
devicesInternational
standardization forIEEE 802.11

IETF

Bluetooth SIG

Sets communication
protocols for wireless
LAN switches and basestations

Exchanges information
on use of the 2.4-GHz
band

3GPP
Exchanges information oncooperation between
wireless LAN and cellular
networks* TAG: Technical Advisory Group (a unified group summarizing and supporting the activities of multiple WGs regarding a particular topic)
3GPP: 3rd Generation Partnership Project
IETF: Internet Engineering Task Force
IMT: International Mobile Telecommunications

ISO/IEC JTC: International Organization for Standardization/International
Electrotechnical Commission Joint Technical Committee
SIG: Special Interest Group

Fig. 1. Positioning of 802.11 WG within the IEEE 802 Standards Committees.

selected, a draft summarizing the basic technicalspecifications is created. The 802.11 WG and theIEEE-SA hold an electronic ballot to vote on thedraft. In each ballot, voting members vote to either
support the specification of the draft or not, and they
optionally attach comments for revision. The TG
resolves these comments by revising the draft as necessary; then the next electronic ballot is carried out.
This process is repeated until the comments areresolved through the ballot and voting process and theapproval rate meets certain prescribed conditions.
Finally, when the proposal receives approval by the
802 Committee, it is published as a standard specification.
3. Status of work in 802.11 WG
The active TGs and SG in the 802.11 WG, as ofJuly 2013, are listed in Table 1. This article focuseson the activities of the following two groups in creating amendments of the 802.11 standard for increasing
throughput. The current state of their work is also
discussed.
Vol. 11 No. 10 Oct. 2013

1.	TGac, which is working on creation of the standard that achieves system throughput of 1 Gbit/s
and greater.
2.	The High Efficiency WLAN SG (HEW SG),
which is preparing to form a TG to work on realizing high system capacity in the dense deployment of wireless LAN access points (APs) andstations (STAs).
3.1 Status of TGac
TGac began its activities in November 2008; these
activities concerned the next generation of wireless
LAN to follow 802.11n, which has been widelyadopted. It assumes use of the 5-GHz band. TGac has
set the following two target values for speed increases:(1)	Throughput of 500 Mbit/s on a single wirelesslink(2)	Total throughput of 1 Gbit/s on multiple wireless links
For target (2), a multi-user MIMO (multiple input,
multiple output) (MU-MIMO) technology that
extends the MIMO technology specified in 802.11n,Global Standardization Activities

Support for US frequencies(3.65-3.7 GHz)

IEEE802.11 (Initial standard)

(11j)

(11d)

(TGaj)
UHF band support (TGah)
TVWS support (TGaf)(11y)

WLAN in vehicular environments (11p)

Support for Japanese frequencies(4.9-GHz band)

International support

Support for China millimeter-wave band

Legend(TGaq)

Interworking with external networks (11u)

Direct links between STAs

(11z)
Extended service
discovery functions

Mesh networks (11s)

Active TG/SG

Wireless network management (11v)Standard completed TG

Radio resource management (11k)
Enhancements to bridge
IEEE 802 specifications (TGak)DFS/TPC (11h)Inter-AP Comm. (11F)

Fast roaming (11r)

Fast initial link setup
Security (11i)(TGai)High Efficiency WLAN
(HEW) SG(11ae)
Video transmission (11aa)

Management frame protection (11w)
Prioritized access for management frames

QoS support (11e)
11b
11a

11g

5-GHz support
1998

2000

High throughput in 2.4/5-GHz band (11n)Very high throughput in 5-Hz band (TGac)
Very high throughput in 60-GHz band (11ad)

2.4-GHz band extension
2002

2004

2006

2008

2012

2010

DFS/TPC: Dynamic Frequency Selection/Transmit Power Control
Inter AP Comm: Inter-Access Point Communication
QoS: quality of service

2013 (year)

TVWS: television white space
UHF: ultra high frequency

Fig. 2. History of IEEE 802.11 standard and its amendments.

Table 1. Active TGs/SG in 802.11 WG.
TG/SG

Focus of study

Completion date(planned)

TGac

Very high throughput below 6 GHz (Systemthroughput of Gbit/s and above)

Draft D7.0

Feb. 2014

TGaf

Wireless LAN in TV white space

Draft D5.0

Jun. 2014

TGah

Wireless LAN supporting wide areas and many
Draft D0.1
terminals under 1-GHz frequency band

Mar. 2016

TGai

Fast initial link setup

Draft D1.0

Feb. 2015

TGaj

Millimeter-wave-band wireless LAN in China

Technology under study

Oct. 2016

TGak

Enhancements for transit links within bridged
networks

Technology under study(undecided)

TGaq

Pre-association service discovery

Technology under study

May 2015

HEW SG Highly efficient wireless LAN SG

is adopted to achieve simultaneous transmission tomultiple STAs over the same frequency band. Experimental results from NTT’s testbed in real environments [2] are being used to confirm the feasibility ofthis technology. The technologies to be adopted havebeen refined over approximately two years since
TGac began its activities, and the work of conducting

Status(As of Sept. 2013)

Usage models and scope under TG to be establisheddiscussionin Jul. 2014

ballots and revising the draft is still continuing. As of
September 2013, the work to resolve comments on
the sixth edition draft (D6.0) had been finished, andefforts are proceeding on target to complete standardization by February 2014.

NTT Technical Review

a
dcba

b
11n
Transmitter cdMax. 4-times
spatial multiplexingabMax. transmit power density

Global Standardization Activities

40 MHz(11n max. channel width)
80 MHz (11ac requirement)* Increases transmit speed by 2.16 times
160 MHz (11ac max. value)* Increases transmit speed by 4.33 times
Frequency(b) Channel width expansioncdcba
hg f eMax. 8-times
spatial multiplexing* Transmission
rate doubledd

11ac
Transmitter efg

11n: 64QAM
11ac: Newly specified 256QAM(Max. 6 bit/symbol)(Max. 8 bit/symbol)* Increase transmit speed by 1.33 times(c) Increase the number of constellation points.

h(a) Expand spatial multiplicity.
QAM: quadrature amplitude modulation

Fig. 3. Technology addressed in 802.11ac focusing on increased speed.

Table 2. Comparison of 802.11ac requirements and maximum values.
Speed increase function/
characteristic

11ac

11n
Regulated max.

Min. value

Max. value

Spatial multiplicity

4

1

8

Transmit bandwidth

40 MHz80 MHz160 MHz

Modulation

64QAM

64QAM

256QAM

Maximum frame size

65,535 Bytes

8191 Bytes

1,048,575 Bytes

Physical layer transmit speed

600 Mbit/s

292.5 Mbit/s

6933.3 Mbit/s

Maximum throughput(Transmission efficiency)

485 Mbit/s(81.0%)

157 Mbit/s(53.4%)

5.85 Gbit/s(84.4%)

Throughput using only the required conditions
and functions is limited to approximately 1/3 ofthe 11n maximum.

3.2 8 02.11ac Specification for throughput
enhancement
For target (1) (increasing the speed of individual
wireless links), the techniques already defined in
802.11n such as spatial multiplexing, and techniques
related to channel bandwidth and the number of constellation points have been extended further (Fig. 3).
Wideband transmission using the 80-MHz or
160-MHz channel specified in 11ac was not previVol. 11 No. 10 Oct. 2013

There is a large difference between the required andoptional functions.
- PHY transmit speed: 23.7 times- Throughput: 37.3 times

ously allowed under Japanese Radio Regulatory
Rules, but recent changes in the regulatory rules inMarch 2013 make it possible to use these bandwidths.
There are also large differences between the mandatory conditions, which must be supported, and the
maximum provisions in 802.11ac (Table 2). This isintended to reflect the diversifying needs of wireless
LAN terminals and to impart high scalability.
To achieve target (2) (increasing system throughputGlobal Standardization Activities

An AP and an STA use spatial multiplexing thatuses multiple antennas to transmit data in parallel.
Specified in 802.11n
AP

Spatially allocated multiple connections with avariety of STAs implemented using transmit
beamforming technique
STA

AP

Space division multiple access(communication with multiple terminals on thesame channel at the same time)[Issue] Spatial multiplexing is not possible for mobile
and other terminals having few antennas.
Spatial multiplexing capabilities of base stations may
be underutilized.

(b) Multi-user MIMO(a) Single-user MIMO

Fig. 4. Depiction of SU- and MU-MIMO.

by transmitting over multiple wireless links simultaneously), MU-MIMO technology is specified for the
downlink (DL) transmissions. An AP transmits to up
to four STAs simultaneously using beamforming
techniques to cancel inter-user interference in orderto implement simultaneous transmission to multiple
STAs.
Single-user MIMO (SU-MIMO) technology, whichtransmits between individual STAs using spatial multiplexing, is already specified in 802.11n. Additionally, 802.11ac defines DL MU-MIMO technology,
which enables increases in transmission efficiency
without requiring multiple receiver antennas or complex signal processing at each destination (Fig. 4).
The 802.11ac standard specifies wireless frame formats, methods for allocating user groups, methods
for channel state information feedback observed ateach STA in order to achieve transmit beamforming,and other aspects needed to implement DL MUMIMO transmission. With DL MU-MIMO technology, even if STAs do not support SU-MIMO technology, the AP’s spatial multiplexing transmission usingtransmit beamforming makes it possible to transmit
multiple frames to different STAs simultaneously
over the same frequency band, which enhances thetotal system throughput.
In addition to a variety of transmission modes

including combinations of spatial multiplexing,
transmission bandwidth, and SU/MU-MIMO transmission, 802.11ac defines the frame format encapsulated in the same header format as 802.11a/n. This
format enables compatibility among 802.11a/n/actransmissions on the 5-GHz band.
3.3 Status of HEW SG
Recently, wireless LAN has been widely deployed.
These networks are now being implemented in
mobile terminals such as notebook PCs, smartphones,
and tablet computers. Transmission speeds have also
increased to up to several hundred Mbit/s with theadvent of 802.11ac. However, the frequencies available for wireless LAN are severely limited. Thesefrequencies are also used by many wireless LAN
systems in crowded environments such as train stations and airports, which results in problems such as
significantly reduced transmission speeds and longer
times required to connect to the network.
The WNG SC has been deliberating on these conditions in its discussions of next-generation wireless
LAN systems to follow 802.11ac since the end of
2011, including the need to increase transmission
efficiency in environments with a high concentrationof terminals. At the March 2013 meeting, a motion toestablish a new SG was approved, which had been
NTT Technical Review

Global Standardization Activities

proposed jointly by 19 companies including NTT.
The motion to establish the HEW SG confirmed theneed to begin working on various issues. The proposal
was as follows.
“Do you support starting a new study group calledhigh efficiency WLAN to enhance 802.11 PHY and
MAC in 2.4 and 5 GHz with a focus on:- Improving spectrum efficiency and area throughput- Improving real world performance in indoor andoutdoor deployments- in the presence of interfering sources, dense
heterogeneous networks- in moderate to heavy user loaded APs?”The HEW SG began its activities at the May 2013
meeting [3]. At that meeting, the following officers of
the SG were elected:- Chair: Osama Aboul-Magd (Huawei Technologies)- Secretary: Yasuhiko Inoue (NTT)
During the May and July meetings, more than 50
contributions were submitted regarding usage models(specific examples of congested environments) andtechnical issues with current wireless LAN standards,
and the SG had a lively discussion on them. At the
July meeting, the SG created the draft version of theconsolidated document of usage models. This document was sent to the Wi-Fi Alliance, and discussions
on prioritization from the perspective of future wireless LAN ecosystems will be held. Next, the contribu-

Vol. 11 No. 10 Oct. 2013

tions from each company will be summarized and theareas requiring study by the SG will be narrowed
down. This will be used to clarify the technical issues
that need to be resolved, clearing the way for creatinga prospectus for establishing a TG.
4. Summary
This article introduced the 802.11 WG anddescribed the state of work on the 802.11ac standard,
which will expand throughput. It also discussed theHEW SG, which is working to standardize highspeed technology for future high-efficiency wirelessLANs. Activity in the HEW SG has just begun, butthere is already much anticipation for the introduction of 802.11ac, the next generation that will further
increase efficiency.
References
[1]

[2]

[3]

K. Nagata, Y. Kojima, T. Hiraguri, and Y. Takatori, “Wireless Local
Area Network Standardization of IEEE 802.11 and the Wi-Fi Alliance,” NTT Technical Review, Vol. 8, No. 4, 2010.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr2010
04gls.html
K. Nishimori, R. Kudo, Y. Takatori, A. Ohta, and K. Tsunekawa,“Performance Evaluation of 8x8 Multi-User MIMO-OFDM Testbed
in an Actual Indoor Environment,” IEEE PIMRC 2006, Helsinki,
Finland.
IEEE 802.11™ High Efficiency WLAN Study Group Created, IEEE
Standard Association, 11 July, 2013.
http://standards.ieee.org/news/2013/IEEE_802.11_HEW.html

Global Standardization Activities

Yusuke Asai

Senior Research Engineer, Wireless Systems
Innovation Laboratory, NTT Network Innovation
Laboratories.
He received the B.E. and M.E. degrees in electrical engineering from Nagoya University,
Aichi, in 1997 and 1999, respectively. Since joining NTT in 1999, he has been engaged in R&D
of broadband MIMO-OFDM techniques forhigh-speed wireless LAN systems and standardization activities for IEEE 802.11n and 802.11ac.
He has been serving as a co-chair of COEX
(coexistence) Ad Hoc in IEEE 802.11ac since2010. He received the Young Engineer Award
from the Institute of Electronics, Information andCommunication Engineers (IEICE) in 2003. He
is a member of IEICE and IEEE.

Yasuhiko Inoue

Senior Research Engineer, Wireless Systems
Innovation Laboratory, NTT Network Innovation
Laboratories.
He received the B.E. and M.E. degrees in electrical engineering from Keio University, Kanagawa, in 1992 and 1994, respectively. In 1994, hejoined NTT Wireless Systems Laboratories,
where he engaged in R&D of a personal handy
phone (PHS) packet data communication system.
He moved to NTT Network Innovation Laboratories in 2010. Since 1997, he has been working on
R&D of IEEE 802.11 wireless LAN systems andhas been participating in standardization activities since 2001. Currently, he is working on the
research, development, and standardization ofhigh efficiency wireless LAN systems. He was avisiting scholar at Stanford University from 2005
to 2006. He received the Young Engineer Award
from IEICE in 2001 and received a Contributor
Award for the IEEE 802.11j standard from theIEEE Standards Association in 2004. He is currently serving as the secretary of the IEEE 802.11
HEW SG. He is a member of IEICE and IEEE.



Yasushi Takatori

Senior Research Engineer, Supervisor, Wireless Systems Innovation Laboratory, NTT Network Innovation Laboratories.
He received the B.E. degree in electrical andcommunication engineering and the M.E. degree
in system information engineering from Tohoku
University, Miyagi, in 1993 and 1995, respectively. He received the Ph.D. degree in wirelesscommunication engineering from Aalborg University, Aalborg, Denmark, in 2005. He joined
NTT in 1995. He is currently working on R&D
of high efficiency wireless access systems as wellas the optical core network. He served as a cochair of COEX Ad Hoc in IEEE 802.11ac from2009 to 2010. He was a visiting researcher at theCenter for TeleInFrastruktur, Aalborg University,
Denmark, from 2004 and 2005. He received theYoung Engineer Award from IEICE in 2000 and
the Best Paper Award of IEICE in 2011. He is asenior member of IEICE and a member ofIEEE.

NTT Technical Review

Practical Field Information about
Telecommunication Technologies

Case Studies of Recent IP Problemsin Homes
Abstract

In this article, we explain some case studies of recent IP (Internet protocol) problems that haveoccurred in homes. This is the nineteenth in a bimonthly series on the theme of practical field informationon telecommunication technologies. This month’s contribution is from the Network Interface Engineering Group, Technical Assistance and Support Center, Maintenance and Service Operations Department,
Network Business Headquarters, NTT EAST.
Keywords: IP problem, IPv6, case study

1. Introduction
A wide variety of terminals have come to be connected to the Internet protocol (IP) network in unisonwith the rapid expansion of Internet services in society. At NTT EAST, the Technical Assistance and Support Center has seen the number of problem incidents
in the IP system increase annually as FLET’S andother IP communication services grow, and it has
been working to identify and explain the causes ofthese IP communication problems using packet-capture analysis. This month’s article describes recent
developments in Internet technologies and introducescase studies of IP problems that have been solved bypacket-capture analysis.
2. IPv4
This section describes recent developments inInternet Protocol version 4 (IPv4) and an associatedproblem.
2.1 IPv4 global addresses
On February 3, 2011, the Internet Assigned Numbers Authority (IANA), the organization that manages
the allocation of IPv4 global addresses used mainlyfor establishing Internet connections, announced thatthese addresses had been exhausted. Then, about twomonths later on April 15, the Japan Network Information Center (JPNIC), the organization in charge of

allocating and registering IP addresses in Japan, alsoannounced the exhaustion of IPv4 addresses. At present, this applies only to IPv4 global addresses allocated to Internet service providers (ISPs) and corporations; the efficient use of existing addresses meansthat Internet usage is continuing as usual. However,as new allocation of IPv4 global addresses is no longer possible, it may not be possible to launch newservices using the Internet via IPv4 connections.
2.2 Case study: slow Internet access
The following describes a problem related to theallocation and exhaustion of IPv4 global addresses.
Specifically, a customer using the FLET’S service
reported that Internet access was sometimes slow.
2.2.1 C ustomer’s equipment configuration andconditions at time of problem occurrence
The equipment and systems used to establish thiscustomer’s Internet connection are shown in Fig. 1. In
this setup, a Point-to-Point Protocol over Ethernet(PPPoE) session is established at the broadband
router, while the customer equipment is connected on
the local area network (LAN) side. After connecting
to the Internet from a home personal computer (PC),the customer sometimes found that the connection
was slow. A check of the broadband router log aroundthe times the problem occurred revealed that PPPoE
sessions had been released ten or more times in one
day, as shown in Fig. 2.
NTT Technical Review

Practical Field Information about Telecommunication Technologies* Internet access is sometimes slow in a PC within the customer’s LAN
Capture pointNTT
FLET’S network

Customer LAN
equipment

ISP network(to the Internet)

Broadband router Optical network unit
(ONU)

Fig. 1. Customer’s Internet connection configuration.

02/03 22:34:37,PPP-IPCP established
02/03 22:34:37,PPP authentication successful
02/03 22:34:37,PPP-LCP established
02/03 22:34:36,PPPoE session initiation successful
02/03 22:34:36,PPPoE AC discovery successful* 02/03 22:34:31,PPPoE session released
02/03 21:55:39,PPP-IPCP established
02/03 21:55:39,PPP authentication successful
02/03 21:55:39,PPP-LCP established
02/03 21:55:39,PPPoE session initiation successful
02/03 21:55:39,PPPoE AC discovery successful
02/03 21:55:34,PPPoE session released
02/03 20:51:16,PPP-IPCP established
02/03 20:51:16,PPP authentication successful
02/03 20:51:16,PPP-LCP established
02/03 20:51:16,PPPoE session initiation successful
02/03 20:51:16,PPPoE AC discovery successful
02/03 20:51:11,PPPoE session released

Fig. 2. Excerpt of PPPoE session release log in broadband
router.

2.2.2 Inspection method and analysis results
We performed packet capture on the wide area network (WAN) side of the broadband router at the times
the problem was occurring and then analyzed indetail all of the captured data corresponding to thetime of that PPPoE session release indicated in the
broadband router log. By doing this, we were able todetermine why the problem was occurring.
(1) Log analysis at PPPoE session release time
We analyzed captured data before and after a
PPPoE session release time as recorded on the broadband router log (Fig. 2). As shown in Fig. 3, thebroadband router first receives and acknowledges a
PPP Termination Request from the network side andthen receives and acknowledges a PPPoE Active Discovery Terminate (PADT) signal, also from the network side. These actions result in the release of the
PPPoE session.
Vol. 11 No. 10 Oct. 2013(2)	Captured data before/after PPPoE session
releaseCaptured data before and after a PPPoE session
release (marked by * in the broadband router log ofFig. 2) are outlined on the log and shown in Fig. 4.
The data indicate that the 10-minute period prior to
the PPP Termination Request from the network was
an idle state between the broadband router and ISP (inthis case, an idle Internet connection). The same wastrue for PPPoE session releases in other time slots; allwere preceded by a 10-minute idle state. As shown in
the figure, about 6 seconds was needed to reestablish
a PPPoE session after its release, so it can be assumed
that the system response would seem slow to the user
if an Internet connection were to be attempted during
such a session-reestablishment period.
2.2.3 Discussion based on analysis results
The analysis results (1) and (2) above indicated that
communications control on the ISP side would
release a PPPoE connection (perform disconnection
processing) if an idle state existed for at least 10 minutes. The ISP most likely does this for allocatedaddresses that are not being actively used, with theintention being to achieve more effective use of IPv4
global addresses.
2.2.4 Cause of problem
The results of analysis suggested that this problem
was caused by communications-control measures on
the ISP side and not by any problems in the FLET’S
network. We therefore contacted the ISP manager inquestion and confirmed that processing to release a
PPPoE connection would indeed be initiated on the
ISP side to recover IPv4 global addresses if an idle
state continued for at least 10 minutes.
Looking forward, we can envision a large-scalerollout of the IPv6 next-generation Internet protocol
Practical Field Information about Telecommunication Technologies

ONU

Broadbandrouter

NTT networkrouter(i) PPP Termination RequestNTT
FLET’S network

ISP- PPP Termination Request* Broadband router performs releaseprocessing after receiving a termination requestfrom the network side.
- PPPoE Terminate (PADT)PPP Termination Ack(ii) PPPoE Terminate (PADT)
PPPoE Terminate (PADT)

Fig. 3. Session release sequence.

Idle time: 10 min
22:24 –
22:34
Release processing

Session-reestablishment
log data

Connection processing

Fig. 4. Captured data before and after session release.

in response to this problem, and we can also consider
the introduction of a mechanism to achieve more
efficient use of IPv4 global addresses.
3. IPv6
This section describes recent developments inInternet Protocol version 6 (IPv6) and an IPv6 Internet connection problem.
3.1 IPv6 features
IPv6 was developed as the next-generation IP tosucceed IPv4, which has been the protocol used tosupport Internet connections to date. As the scale ofthe Internet grew over the years, a number of shortcomings in IPv4 came to light, the most obvious ofwhich is the exhaustion of IPv4 global addresses.
Another problem is network address translation(NAT) traversal.
The aim of NAT traversal is to use IPv4 global
addresses efficiently (economically) on the WAN
side. With this method, a broadband router canincrease the number of connected terminals by using
private addresses on the LAN side and converting
addresses by NAT (more accurately, network address
and port translation (NAPT) since the processincludes port translation). This method, however,prevents a terminal on the LAN side from being
directly specified from the outside, thereby hampering bidirectional communications. Specifically, it can
result in complicated settings and problematic communications in such applications as 050-type IP telephony and online multiplayer games.
In contrast to the above, IPv6 extends the address
NTT Technical Review

Practical Field Information about Telecommunication Technologies

Table 1. IPv4 and IPv6 features.
Version

IPv4

IPv6

Address length (number of addresses)

32 bits (about 4.3 billion)

128 bits (about 3.4 × 1038)

Address notation method

Decimal notation

Hexadecimal notation

Address allocation method

Specifications do not provide for
automatic allocation of addresses,
so other mechanisms must be used.

Specifications provide for automatic
allocation of addresses.

2001:db8:8012:a34b:9056:d78e:f90a:b1c2

IPv6 address format

2001:db8:0000:0000:0000:0000:03ad:c4d5
2001:db8:0:0:0:0:3ad:c4d5
IPv6 abbreviated address format

Leading zeros
may be omitted

2001:db8: :3ad:c4d5
The double colon (::) can be used
only once in an address
Leading zeros in each section of four hexadecimal digits are to be omitted.
For example, 0db8 is written as db8, and 0000 is simply written as 0.
Consecutive four-digit sections of 0s are replaced by a double colon (::) wherever possible.
If only one four-digit section of 0s appears in the address, it is not replaced by a doublecolon (::).
If there are multiple fields that can be replaced by a double colon (::), the field with the mostfour-digit sections of 0s is to be replaced by a double colon (::). However, if the number offour-digit sections of 0s is the same for all replaceable fields, the forward field shall be
replaced by a double colon (::).

Fig. 5. IPv6 address notation.

space to 128 bits, thereby resolving the problem of an
insufficient number of global IP addresses. The features of IPv4 and IPv6 are listed in Table 1. IPv4 uses
32-bit addresses, which means that it can handle 232
or about 4.3 billion IP addresses. However, with 128bit addresses, IPv6 can handle 2128 or about 3.4 × 1038
IP addresses, a significantly larger number. If all ofthese IP addresses were to be allocated to the entire
human race (which we set to 7 billion people for calculation purposes), the number of addresses per person would turn out to be 480 × 1026. It can therefore
be said that the number of IPv6 addresses that can be
implemented is essentially infinite. The IPv6 specifications also feature enhanced security functions andthe addition of Internet Protocol Security (IPsec) as astandard function enabling the creation of a secureVol. 11 No. 10 Oct. 2013

communications environment.
3.2 IPv6 address notation
The IPv6 address notation method is shown in
Fig. 5. Since the address space has been extended to
128 bits in IPv6, a hexadecimal (0–f) notation method
has been adopted that divides the 128 bits (16 bits ×8) into 8 groups of 16 bits connected by colons.
Furthermore, as shown in Fig. 6, the IPv6 unicast
address used for Internet connections treats the first64 bits of the 128-bit address as a subnet prefix andthe last 64 bits as an interface identifier making for aclearly defined address format. In IPv4 addresses, thebit sequences for the network address and hostaddress could change, which means that address
processing at network interfaces has been mainlyPractical Field Information about Telecommunication Technologies

Subnet prefix

Interface identifier

64 bits

64 bits
128 bits

The interface identifier of a unicast address beginning with other than binary 000 is
configured in Modified EUI-64 format with a length of 64 bits.
The boundary between the network-identifying and node-identifying sections is variable
in IPv4 but fixed in IPv6.

Fig. 6. IPv6 unicast address structure.

(2) Router Solicitation (RS) message(1) Power ON
IPv6-compatible router

IPv6-compatible
terminal

RA: Router Advertisement
RS: Router Solicitation

IPv6 network(4) Automatic generation(3) Router Advertisement (RA) message

Fig. 7. IPv6 automatic address generation method.

handled by software. In short, while achieving highspeed processing was problematic with IPv4
addresses, this uniform method of using bit sequencesin IPv6 addresses means that high-speed processing
can be achieved by hardware.
3.3 IPv6 address allocation method
Unlike IPv4, the address allocation method specified by IPv6 automatically allocates IP addresses forestablishing IPv6 connections. This IPv6 automatic
address generation scheme, called IPv6 plug andplay, is shown in Fig. 7. The convenience of IPv6
plug and play is analogous to the ease of using a home
appliance by simply plugging it into a power outlet on
a wall. When a LAN cable is connected to an IPv6compatible terminal (and authentication is performedin the case of a wireless LAN) (1), the terminal transmits a Router Solicitation (RS) message (2), and an
IPv6 router in the network returns a Router Advertisement (RA) message (3). The IPv6-compatible
terminal then extracts from this RA message theinformation needed to automatically generate an IPv6
unicast address (4). The above process can be mainly
accomplished by hardware, which means that an IPv6
unicast address can be configured in even less timethat it takes to boot up the OS (operating system) on
a PC running Windows.
3.4 Toward full-scale deployment of IPv6
The World IPv6 Launch was held on June 6, 2012as a global event to introduce the new protocol. The
intention behind this event was to convey the idea that
IPv6 would be supported on an ongoing basis wellbeyond the launch date. This includes support forIPv6 standards by IP-network-compatible terminals
to be marketed in the future as well as IPv6 support
for website connections. The holding of this event
signified a transition to a full-scale IPv6 deployment
stage.

NTT Technical Review

Practical Field Information about Telecommunication Technologies* Security tool could not be downloaded.
Capture pointNTT
NGN
Customer’s PC

ISP network(to the Internet)

ONU

Fig. 8. Customer’s Internet connection configuration.

3.5 C ase study: Security Tools cannot be
downloaded on FLET’S HIKARI NEXT
We present here a case study of a problem related to
IPv6 connections. Specifically, a customer subscribing
to the FLET’S HIKARI NEXT High-speed Typebroadband access service was unable to download
Security Tools (the name of this service at NTT
WEST, but called FLET’S VIRUS CLEAR v6 at
NTT EAST) from FLET’S simple setup tools. Additionally, while IPv4 Internet communications presented no problems, connections to IPv6 sites such as
an IPv6 service information site could not be
achieved.
3.5.1 C ustomer’s equipment configuration andconditions at time of problem occurrence
The customer’s Internet connection configurationis shown in Fig. 8. Here, one PC running Windows 7
was connected to the ONU, and Internet connections
to the PC were established using installed startup
tools (i.e., PPPoE connection functions in the OS). In
this environment, IPv4 Internet communications
were able to be performed without incident, but Security Tools could not be downloaded from the FLET’S
simple setup tools.
3.5.2 Inspection method and analysis results
We performed packet capture between the ONU
and PC at the time the problem occurred. We also
performed packet capture when connecting a test PC
that was shown to be capable of downloading Security Tools, and we compared and analyzed the captured data between these two PCs.
(1) Problem trigger
The sequence flow at the time of a Security Tools
download-destination connection failure is shown in
Fig. 9. To begin with, the series of operations fromturning on the PC to determining the IPv6 unicast
address for connecting to the FLET’S HIKARI
Vol. 11 No. 10 Oct. 2013

NEXT service (NGN: Next-Generation Network),
was executed normally. This was followed by nameresolution (DNS: Domain Name Service) of the URL(uniform resource locator) for the Security Tools
download destination, which was likewise performed
without any problems.
Next, the PC transmitted a hypertext transfer protocol (HTTP) synchronize (SYN) request to initiate the
HTTP connection process. Immediately after this, theNTT network router transmitted a Neighbor Solicitation (NS) message (media access control (MAC)
address request in IPv6 communications) to the PC’s
NGN unicast address. However, no Neighbor Advertisement (NA) message (MAC address reply in IPv6
communications) was subsequently transmitted fromthe PC side, so the NTT network router entered a statein which it could not move to the next sequence.
Finally, after the PC repeated the transmission of the
HTTP SYN request three to four times, the connection terminated. At this time, the message “Cannot
Display” appeared on the PC browser’s screen. The
above analysis led us to conclude that there was somereason why NA messages were not being transmitted
from the PC side.
(2) PC operation at time of problem occurrence
In searching for the reason why no NA messages
were being transmitted from the PC, we found that
NA transmission for that NGN unicast address was
being blocked by the PC’s Windows firewall.
3.5.3 Discussion based on analysis results
We also found that default settings for the Windows
firewall do not block NA transmissions. However,depending on the security software preinstalled inPCs, settings that restrict IPv6 communications canalso be made, and we surmise that those default settings were changed at the time of product shipment.

Practical Field Information about Telecommunication Technologies

ONU
PC

NTT network router
RS: Router Solicitation
RA: Router Advertisement

PC transmits an immediate request for RA (NGN prefix information etc.).
NTT network router returns RA.

NS: Neighbor Solicitation

PC checks for any duplicates of the automatically generated NGN unicast
address by broadcasting.

PPPoE connectionprocessing begins
PPPoE connection completed

PS establishes session by a PPPoE IPv4 connection.

Connection processing to the Security Tools download destination begins.
DNS query AAAA
DNS query respons AAAAHTTP SYN
NS: Neighbor Solicitation
NS: Neighbor Solicitation
NS: Neighbor Solicitation
NA: Neighbor Advertisement
HTTP SYN/ACK

PC submits DNS query AAAA for IPv6 name resolution.
Reply from NGN DNS
PC begins HTTP connection processing.
NTT network router transmits NS(PC’s NGN unicast address) by broadcasting.
Retransmits NS repeatedly since no reply received
Since no NA (reply to a MAC address request) is received
from PC, the system enters a state in which no HTTP
SYN/ACK can be returned.

SYN/ ACK: synchronize/acknowledge

Fig. 9. Sequence at time of Security Tools download-destination connection failure.

3.5.4 Cause of problem
The search for the reason why no NA messages
were being issued by the customer’s PC revealed that
NA transmissions for that NGN unicast address werebeing blocked due to that PC’s Windows firewall
settings. This is why the PC entered into a state inwhich it could not connect with an IPv6 site. Consequently, changing the Windows firewall settings or
temporarily disabling the firewall made it possible toconnect to the Security Tools download site anddownload those tools. This case study underscores
the importance of checking PC settings in the eventthat specific types of communications cannot be performed.



4. Conclusion
In this article, we gave an overview of the IPv4 andIPv6 protocols and introduced two case studies ofrecent IP problems experienced by customers in theirhomes. New services and products using IP connections are constantly being launched, and the IP network within customers’ homes is becoming increasingly diversified and complex. The Technical Assistance and Support Center is committed to uncovering
the causes of IP-related problems and to finding early
solutions.

NTT Technical Review