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A to G

Access Circuit

Access circuit is a telecommunications circuit to connect between facilities of telecommunications carriers and subscribers.

American Depository Receipts/Shares (ADR/ADS)

American Depository Receipts/Shares (ADR/ADS) are securities representing shares of common stock, used to exchange securities of non-U.S. companies in the United States.

Application Service Provider (ASP)

Application Service Provider (ASP) is a company or a service that provides business applications to customers over the Internet.

Artificial Intelligence(AI)

Artificial Intelligence(AI) is intelligence exhibited by machines, rather than humans or other animals.

B Flet's

B Flet's is a type of Flet's access service providing Internet connectivity over optical fibers, provided by Nippon Telegraph East and West Corporation.

Back-office Systems

Back-office systems are network systems providing business functions.


Backbone is the primary part of the network. For ISP, the backbone is the main network connecting NOC, POP and access points over high-speed circuits.

Backbone Router

Backbone router is a router installed at POP to construct a backbone. Backbone router is capable of connecting high speed telecommunications circuits such as several Gbps as the circuits are used for backbone.


bps stands for "bit per second" and is a basic unit of data communications. bps is a number of bits (amount of data) that can be transmitted per second. Other than bps, units such as kbps (1kbps = 1,000bps), Mbps (1Mbps = 1,000 kbps), Gbps (1Gbps = 1,000 Mbps) and Tbps (1Tbps = 1,000Gbps) are often used.


Broadband is a service realized by expansion of high-speed access networks. Broadband also provides full-time connectivity.

Cloud Computing

Cloud computing is a type of service that enables customers to use computing resources over the Internet rather than having local servers or personal devices to handle applications.

Container-based data center

Container-based data center is a data center utilizing container-modules with outside-air conditioning systems. This type of data center offers advantages such as shorter construction period, cost reduction, scalability, and energy savings compared to traditional building-type data centers. For details about IIJ’s business with container-based data center, please refer to


Content stands for information that is found on the web, such as text, music and videos.


Cracking is the practice of engaging in ill-intentioned activities such as gaining unauthorized access to computer systems using security holes, and stealing and altering data and computer programs.

Connected Home

A home in which household items and aspects of daily life are connected to a network to improve the convenience of living.

Content Delivery Network (CDN)

Content Delivery Network (CDN) is a geographically distributed network of proxy servers and their data centers.

Data Center

Data center is a facility built to house computer systems. Data centers usually have facilities for computer systems, such as racks, electric facilities and air conditioning facilities, facilities that help recover from disasters such as earthquakes and power outages, and security facilities such as access control. There are Internet Data Centers (iDC) to provide Internet connectivity in data centers. The most up-to-date map of IIJ's data centers can be found here.

Dedicated Access Services

Dedicated access services are Internet connectivity services using private lines. Dedicated access services enables wide-speed and full-time Internet connectivity.

Dial-up Access Services

Dial-up access services are Internet connectivity services using public switched telephone network and radio circuits such as Personal Handy-phone System (PHS). Dial-up access services require connection each time when Internet is to be used. However, users can connect to Internet for a low price and from everywhere by using popular public telephone circuits.

Distributed Denial of Service (DDoS) attack

Distributed Denial of Service (DDoS) attack is a malicious attempt to make a server or a network resource unavailable by flooding them with many packets distributed by many devices and multiple Internet connections.

DNS Server

DNS server is a computer that provides a function of hierarchical database, Domain Name System (DNS) over the Internet. DNS is currently used to match an IP address that points to a location on the network and a domain name that is mainly used for an email address.


Ethernet is a global standard for cabling computers together in a network and the most widely-installed local area network (LAN) technology.

Embedded SIM (eSIM)

Embedded SIM (eSIM) refers to SIM chip embedded in a communication device.


Flet's is a name of various services using telecommunications circuits such as optical fibers and ADSL, provided by Nippon Telegraph and Telephone East and West Corporation. Flet's includes access services to provide Internet connectivity tying up ISPs and application services such as content distribution and VPN services.

Flet's ADSL

Flet's ADSL is a type of Flet's access services providing Internet connectivity over ADSL (Asymmetric Digital Subscriber Line) using existing telephone lines.

Frame Relay (FR)

Frame Relay (FR) is one of the data communication services using packet communications. FR is widely used to construct Wide Area Network (WAN) in enterprises since it is more cost effective and has higher speed compared to existing packet communications services.


A new word that combines the terms Financial and Technology.


Compared to conventional MVNO (light MVNO), which is highly dependent upon MNO equipment, full MVNO services are operated using an in-house HLR/HSS (databases for managing SIM cards), thereby making it possible for such providers to procure and issue their own SIM cards and design their services with more freedom.

H to N

Home Energy Management System (HEMS)

Home Energy Management System (HEMS) offers management, monitoring and control of selected devises for residential buildings.

Housing Services

Housing services are services that provide locations for computer systems in a data center.

Infrastructure as a Service (IaaS)

Infrastructure as a Service (IaaS) is a service model that provides remote customers with computing infrastructure such as hardware, storage, servers, network components, etc. on the Internet.

Inexpensive data communications services with SIM cards

Inexpensive data communications services with SIM cards are usually services provided by MVNOs. The monthly fee is much less expensive than those of traditional mobile carriers as MVNOs' services have some limitation such as bundled data volume.

Information and Communication Technology (ICT)

Information and Communication Technology (ICT) is a general term of technologies in relation to hardware, software, system and data communication used for information communication by computer.

Internet Architecture Board (IAB)

Internet Architecture Board (IAB) is a group which considers general technological issues of the Internet. IAB belongs to the Internet Society (ISOC) and manages technology related organizations such as Internet Engineering Task Force (IETF).

Internet Engineering Task Force (IETF)

Internet Engineering Task Force (IETF) is an organization formed to settle on standardization of technologies used on the Internet. The standard specifications settled on are published as Request For Comment (RFC) and others.

Internet Exchange (IX)

Internet eXchange (IX) is a point for ISPs to exchange each other's Internet traffic. IX was started to be used as a place for ISPs to connect to each other easily, as there came out many ISPs along with the expansion of Internet and interconnectivity among ISPs became complicated.

Internet of Things (IoT)

Internet of Things (IoT) enables not only physical objects but any “things” connected to network to exchange information automatically.

Internet Protocol (IP)

Internet Protocol (IP) is the protocol that is used on the Internet. IP is a type of packet switching that transmits telecommunications data by a unit called "a packet" and an IP address is allocated to equipment to point to a location. IP became one of the most popular protocols as the Internet spread.

Internet Protocol Version 6 (IPv6)

Internet Protocol version 6 (IPv6) was planned as a new protocol to take the place of Internet Protocol version 4 (IPv4) because the Internet's rapid growth led to an IP address shortage. IPv6 was planned as a new protocol because a problem of shortage of IP address was raised as Internet rapidly spreads, while Internet Protocol version 4 (IPv4) is currently used on the Internet. IPv6 has characteristics of vast address fields, enhanced security, increased speeds and advanced functions.

Internet Service Provider (ISP)

Internet Service Provider (ISP) is a company that provides Internet connectivity, web hosting and other services.


Intranet is a network built within an organization with Internet technology. Intranet is widely used in enterprises and governmental organizations, because it can be used in the same way as the Internet and it can be built for a relatively low price with popular technology.

IP Address

IP Address is a number allocated to recognize individual equipment on an IP network. IP address is used as a source and destination when data communication is made. The length of an IP address becomes 128 bit for IPv6, which is 4 times greater than 32 bit for IPv4.

Japan Network Access Point (JPNAP)

JaPan Network Access Point (JPNAP) is an Internet Exchange (IX) operated by Internet Multifeed Co., and is one of the major IXs in Japan. JPNAP is located in Tokyo and Osaka.

Local Area Network (LAN)

Local Area Network (LAN) is a network connecting computers and other equipment in a relatively narrow area, such as the same fields and the same building. A broader network is called Wide Area Network (WAN) .

Machine to Machine (M2M)

Machine to Machine (M2M) enables devices connected to network to exchange information automatically and perform designed actions.

Mission Critical System

Mission critical system is a system that is essential to business operations. Trouble of mission critical systems causes a great loss and/or loss of trust.

Mobile Number Portability (MNP)

Mobile Number Portability (MNP) enables users to retain their mobile phone number when switching mobile carriers.

Mobile Virtual Network Enabler (MVNE)

Mobile Virtual Network Enabler (MVNE) provides mobile infrastructure and related services to MVNOs.

Mobile Virtual Network Operator (MVNO)

Mobile Virtual Network Operator (MVNO) is a company that provides mobile phone services by using other company's network infrastructure.

Network Function Virtualization (NFV)

Network Function Virtualization (NFV) is often defined as a technology that virtualizes functions previously implemented using dedicated devises and instead, implements them as software on standard high-volume servers.

Network Operation Center (NOC)

Network Operation Center (NOC) is a center used for operating and monitoring networks. Network operation center may also mean Point of Presence (POP).

Network Systems

Network systems are computer systems connected by networks, consisting of routers, telecommunications circuits, servers and others. It is common that network systems provide functions to use applications over an intranet and the Internet.

O to U

On-line Securities Trading Company

An on-line securities trading company is a company that conducts securities trading over the Internet. There are companies that conduct securities trading business sorely over the Internet.

Open Source

Open source is one of various means of licensing software. Open source is defined by an organization named Open Source Initiative (OSI), an organization that promotes open source, and is defined as source code for computer programs that is public and is freely allowed to be re-distributed without worry of copyright or patent infringement.

Original Equipment Manufacturing (OEM)

Original Equipment Manufacturing (OEM) refers to companies that manufacture products under the brand of other companies and is also used as one of the service provisioning methods.


Peering is for networks connected to each other to exchange route information to transmit each other's traffic. Especially for ISP, peering is used to transmit each other's network traffic at IX.

Point of Presence (POP)

Point Of Presence (POP) is a place prepared by an ISP to connect its users to the Internet. In POP, backbone routers to be connected to the Internet backbone and routers to accommodate connectivity from users are installed.


Protocol is to define procedures and form of data required for communication in advance.

Private cloud

Private cloud refers to a model of cloud computing where IT resources such as storage and services are provisioned over private IT infrastructure for the dedicated use of a single organization.

Proof of Concept (PoC)

Proof of Concept (PoC) is a demonstration with the purpose to verify certain concepts or theories have the potential for real-world application.

Public cloud

Public cloud refers to a model of cloud computing where IT resources such as storage and services are provisioned of storage and computation to the general public over the Internet.

Radio Frequency Identification (RFID)

Radio Frequency IDentification (RFID) is a technology by which ID numbers are exchanged and are allocated mainly to recognize individual items over the radio. RFID is better known for being used for Supply Chain Management (SCM). RFID is recognized as one of the technologies with great potential in a ubiquitous society, where computers are installed everywhere in the future.


Router is equipment used to exchange data on a network. A router is usually connected to more than one network and provides switching functionality by sending data that it receives from each network to another appropriate network in accordance with the routing information that it holds.

Software as a Service (SaaS)

Software as a Service (SaaS) is a service model that provides remote customers with access to software on the Internet.

Sarbanes-Oxley Act

Sarbanes-Oxley Act is legislation enacted in July 2002 intending to bring about drastic reforms in corporate governance and information disclosure, to recover reliability of securities markets in the United States that was lowered by the scandals related to accounting of enterprises in the United States, such as Enron scandals. Sarbanes-Oxley Act is applied to a company listed on the markets in the United States.


Security stands for measures that are taken to keep networks, computers, or other such items safe. On a network, this could include installing firewalls to protect internal information systems from broader Internet users.

Security Policy

Security policy is generally made to summarize policies related to information security. Security policy usually rules important policies related to information security, including management policy on information assets such as personal information and management policy on risks such as troubles, and rules detailed procedure to keep security. Security policy is the most basic document related to information security measures.


SEIL is a next generation router developed by IIJ. SEIL is installed at customer premises and used to connect to the Internet and Virtual Private Networks (VPN). SEIL has a SEIL Management Framework (SMF) function for central management of various network functions.

SEIL Management Framework (SMF)

SEIL Management Framework (SMF) is a framework to centrally manage network connections and other functions and a service to provide the functions on SEIL, IIJ's originally developed routers and other network equipment. SMF enables connections to the Internet by simply connecting routers to telecommunications lines without complicated configurations.


Server is a computer system or program to provide services, such as email and web services to other computers and their users.

Service Level Agreement (SLA)

Service Level Agreement (SLA) is an agreement to show objective figures to evaluate service quality and to reimburse service charges when the level of service is under the defined service quality. IIJ adapts Service Level Agreements to Internet connectivity services and sets objective figures for availability, network latency and others.

Software Defined Network (SDN)

Software Defined Network (SDN) is an approach to managing networks. In a software defined network, a network administrator can construct and manage the network flexibly since it is controlled by software.


Spam is unsolicited email. Users typically do not want to receive spam, such as advertisement emails without any permission and emails sent for fraud.

Systems Integration (SI)

Systems Integration (SI) is to meet customer needs by designing, constructing and operating information systems suitable to customer needs.

Systems Integrator

Systems integrator is a company that provides systems integration to end customers.

Smart Factory

A manufacturing environment that enables work processes to be improved through the automation and optimization of production management at the site using IoT and industrial robots.

Targeted cyber attack

Targeted cyber attack is an attack targeting a specific individual or organization through Internet.

Telecommunications Carrier

Telecommunications carrier is a company that provides telecommunications services by installing telecommunications equipment such as access circuits and telephone switch boards.

Total Solutions

Total solutions are one form of business to provide or propose solutions to solve multiple problems comprehensively. A company that provides total solutions related to network operation is called a total network solution provider.


Traffic is a flow of data transmitted over a network. Traffic may also relate to the amount of data transmitted.

V to Z


High definition resolution with four times the number of pixels (3,840×2,160) as full high resolution (1,920×1,080).

Virtual Private Network (VPN)

Virtual Private Network (VPN) is a technology to provide a virtually closed network, such as a corporate intranet over the open network Internet with encryption technology and other security measures.

Voice over IP (VoIP)

Voice over IP (VoIP) is a technology to provide voice communications over the Internet, such as Internet telephony.

Wide Area Network (WAN)

Wide Area Network (WAN) is a network connecting computers and other equipment in a relatively broad area. A WAN consists of two or more LANs.

Wide-area Ethernet

Wide-area Ethernet is a service to connect networks that are in the different locations by Ethernet. With the service, LAN can be expanded to WAN as LAN is usually constructed by Ethernet.

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