32-bit ASN – 32-bit Autonomous System Numbers
32-bit Autonomous System Numbers (ASNs) are an update to the original 16-bit ASN format. 32-bit ASNs (also referred to as ASN32s, four-byte ASNs or four-octet ASNs) represent an expansion of the existing ASN numbering space.

AfNOG – Africa Network Operators’ Group
An educational and operational forum for the coordination and dissemination of technical information related to backbone/enterprise networking technologies and operational practices in Africa.
www.afnog.org

AIS – Africa Internet Summit
Africa Internet Summit is a multi-stakeholder event combining conference, training and networking for the Internet industry in Africa. The annual summit attracts internationally renowned speakers to share knowledge and experiences on technology developments, changes, uses and effects.
www.internetsummitafrica.org

AFRINIC – African Network Information Center
The Regional Internet Registry (RIR) serving Africa and some countries located in the Indian Ocean.
www.afrinic.net

Aggregation
This refers to the “summarization” (or aggregation) of routing information and limiting the number of routing table entries. Hierarchical (provider-based) distribution supports aggregation.

Allocation
The range of addresses reserved for a Local Internet Registry (LIR) or Internet Service Provider (ISP) for sub-allocation and assignment to End Users or to the LIR’s own network.

APNG – Asia Pacific Networking Group
An organization that aims to promote the Internet and the coordination of network inter-connectivity in the Asia Pacific region.
www.apng.org

APNIC – Asia Pacific Network Information Centre
The Regional Internet Registry (RIR) serving the Asia Pacific region.
www.apnic.net

APRICOT – Asia Pacific Regional Internet Conference on Operational Technologies
A forum for Internet players in the Asia Pacific region to learn from their peers and the global Internet community.
www.apricot.net

ARIN – American Registry for Internet Numbers
The Regional Internet Registry (RIR) serving Canada, many Caribbean and North Atlantic islands, and the United States.
www.arin.net

arpa (or “.arpa”)
The Address and Routing Parameters Area top-level domain, used for network infrastructure including the reverse DNS zones for IPv4 and IPv6, in-addr.arpa and ip6.apra.

ASO – Address Supporting Organization
One of the supporting organizations recognized by the ICANN bylaws. The ASO reviews recommendations on IP address policy and advises the ICANN Board on these matters.
www.aso.icann.org

ASO AC – Address Supporting Organization (ASO) Address Council (AC)
The ASO AC oversees recommendations on global IP address policy, including the management of policy development activities and appointments to the ICANN Board of Directors. See also: NRO Number Council (NC).
www.aso.icann.org/ac

ASO MoU – Address Supporting Organization (ASO) Memorandum of Understanding (MoU)
An agreement between ICANN and the Regional Internet Registries (RIRs) for forming and operating the ASO.
www.aso.icann.org/documents/memorandum-of-understanding-1999/

Assignment
A range of addresses that is registered for a specific purpose, either for an End User, ISP or Local Internet Registry’s (LIR) network infrastructure.

AS – Autonomous System
A group of IP networks, operated by one or more network operators, that has a single and clearly defined external routing policy. Used by Border Gateway Protocol (BGP) and uniquely identified by an ASN.

ASN – Autonomous System Number
A unique identifier for an Autonomous System (AS) that is used in the exchange of exterior routing. Managed under the RIR system, ASNs were extended in 2009 from 16 to 32 bits in length.

BGP – Border Gateway Protocol
An Internet protocol commonly used within and between Internet Service Providers (ISPs).

BGP Origin Validation
Origin validation helps to prevent the unintentional advertisement of BGP routes. It is a mechanism by which route advertisements can be authenticated as originating from an expected autonomous system (AS).

BoF – Birds of a Feather
Informal group discussions on topics of specialized interest.

Bogon
An IP packet that claims to be from IP address space reserved by the Internet Assigned Numbers Authority (IANA) or a delegated Regional Internet Registry (RIR). Areas of address space that are not yet delegated, or are reserved for private or special use, are called ‘bogon space’.

CC
E.164 Country Code (as referenced in ITU-T Recommendation E.164).
http://www.itu.int/net/itu-t/inrdb/e164_intlsharedcc.aspx?cc=881,882,883

ccTLD – country code Top-Level Domain
The Top-Level Domain (TLD) corresponding to a country, territory, or other geographic location (.nl for example). See related “CC” above.

Certification
See Resource Certification (RPKI).

CIDR – Classless Inter-Domain Routing
A method of categorizing IP addresses for the purpose of allocating IP addresses to users and for efficiently routing IP packets on the Internet. Allowed deprecation of classful IP address architecture.

Classful IP Addressing
The addressing architecture that was used to allocate Internet number resources until 1993, and specifying five classes: A,B,C,D and E (of which A, B and C were allocated to networks). It was replaced by Classless Inter-Domain Routing (CIDR), which enables more efficient assignment of Internet number resources.

DNS – Domain Name System
The distributed database of information that translates a domain name to an IP address. It also lists the mail servers accepting email for each domain.

DNSSEC – DNS Security Extensions
A technology that provides Domain Name System (DNS) with data integrity and authentication mechanisms, through the use of cryptographic digital signatures.

Domain name
As part of the Domain Name System, domain names identify IP resources, such as an Internet website.

End User
An entity receiving IP address assignments exclusively for use in operational networks and not for reassignment to other organizations.

ENOG – Eurasia Network Operators’ Group
ENOG is the regional forum in which Internet experts concerned with the core operational issues of the Internet can share knowledge and expertise on issues unique to the Russian Federation, CIS, and Eastern Europe.
www.enog.org

ENUM
The IETF protocol that maps E.164 telephone numbers to Internet services using the DNS. See https://tools.ietf.org/html/rfc6116

Global Unicast Address
A globally unique identifier for a single network interface. Other than the exceptions documented in the table linked below, the operators of networks using specific addresses can be found by referring to the Whois servers of the RIRs listed in the registry at: http://www.iana.org/assignments/ipv6-unicast-address-assignments

gTLD – generic Top-Level Domain
Top-Level Domains (such as .com, .net, .edu) that are not associated with country codes. They are generally privately owned and managed, and any individual or organization can apply through ICANN to establish a new gTLD.

IAB – Internet Architecture Board
The IAB is an IETF committee and an advisory body of the Internet Society (ISOC). Its responsibilities include architectural oversight of IETF activities, Internet Standards, and the appointment of the Request for Comment (RFC) Editor.
www.iab.org

IANA – The Internet Assigned Numbers Authority
IANA is a set of functions that covers the global coordination of the DNS Root, IP addressing, and other Internet protocol resources. ICANN is currently contracted to carry out the IANA functions.
www.iana.org

ICANN – Internet Corporation for Assigned Names and Numbers
The not-for-profit multistakeholder organization responsible for the coordination of the Internet’s unique identifiers including the management of the Domain Name System (DNS) and the distribution of Internet number resources to the Regional Internet Registries (RIRs).
www.icann.org

IESG – Internet Engineering Steering Group
Part of ISOC and responsible for technical management of IETF activities and the Internet standards process.
www.ietf.org/iesg

IETF – Internet Engineering Task Force
An international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet.
www.ietf.org

IGF – Internet Governance Forum
A global multistakeholder forum to discuss public policy matters and other issues related to the global deployment of the Internet. The IGF was established based on the outcomes of the WSIS (World Summit on Information Society).
www.intgovforum.org

in-addr.arpa
In the .arpa domain, the subdomain for IPv4 addresses (as names) for host names.

Internet governance
Internet governance is the development and application by governments, the private sector and civil society, in their respective roles, of shared principles, norms, rules, decision-making procedures and programs that shape the evolution and use of the Internet.

Internet Registry
An organization that is responsible for distributing IP address space to its members or customers and for registering those distributions. IRs include: (i) Regional Internet Registries (RIRs); (ii) National Internet Registries (NIRs); (iii) Local Internet Registries (LIRs).

Internet resources
Refers to IPv4 and IPv6 address blocks and AS Numbers as numeric Internet resources.

IP address – Internet Protocol address
A unique numerical address used to identify a particular piece of hardware connected to the Internet. An IP address serves two principal functions: host or network interface identification and location addressing.

IPv4 – Internet Protocol version 4
A method of identifying IP addresses as 32-bit numbers usually expressed as a “dotted-quad” of four octets. Each octet is expressed as a number between 0 and 255. For example, 207.142.131.235.

IPv4 exhaustion
The term used to describe the depletion of the pool of available IPv4 address space. The Internet Assigned Numbers Authority’s (IANA) pool of IPv4 address space was deemed exhausted on 3 February 2011 after it delegated its last five /8 address blocks to the RIRs.

IPv6 – Internet Protocol version 6
A method of identifying IP numbers as 128-bit numbers in eight 16-bit pieces using hexadecimal values.

IRR – Internet Routing Registry
A collection of routing policy databases that use the Routing Policy Specification Language (RPSL).

ISOC – The Internet Society
A membership organization, providing leadership in a range of issues that confront the future of the Internet. It is also responsible for providing administrative support to the IETF.
www.isoc.org

ISP – Internet Service Provider
A person or organization that provides an End User with access to the Internet.

ITU – International Telecommunication Union
A United Nations (UN) affiliated Member State organization with global treaty level recognition for telecommunications technologies.
www.itu.int

IXP – Internet Exchange Point
A physical infrastructure that allows different Internet Service Providers (ISPs) to exchange Internet traffic between their networks (Autonomous Systems), often by means of peering agreements that determine arrangements for traffic exchange.

LACNIC – Latin American and Caribbean Network Information Center
The Regional Internet Registry (RIR) serving the Latin America and Caribbean region.
www.lacnic.net

Legacy Resources
A legacy Internet number resource is an IPv4 address or Autonomous System number that was issued by an Internet Registry (InterNIC or its predecessors) prior to the formation of a Regional Internet Registry with responsibility for address distribution in the relevant geographic region.

LIR – Local Internet Registry
An Internet Registry (IR) that primarily assigns address space to the users of the network services that it provides. LIRs are generally ISPs whose customers are primarily end users and possibly other ISPs.

MENOG – Middle East Network Operators Group
A forum for network operators to identify areas of cooperation in the Middle East region and to exchange experience and knowledge.
www.menog.net

Multicast
These addresses are used to identify multicast groups. They should only be used as destination addresses, never as source addresses.

Multi-homed
Describes a network that has upstream Internet connections, which may be permanently or temporarily routed. A multi-homed host is physically connected to multiple data links that can be on the same or different networks.

Name server
A server that resolves Internet domain names into IP addresses and vice-versa.

Name vs Address vs Route
A name identifies an endpoint, an address tells where it is, and a route tells how to get there.

NANOG – North American Network Operators Group
An educational and operational forum for the coordination and dissemination of technical information related to backbone/enterprise networking technologies and operational practices in the North American region.
www.nanog.org

NAPTR – Number Authority Pointer
Used within IETF RFC 2916 to identify possible URLs and numbers that can be returned.

NAT – Network Address Translation
The process of modifying a network address while in transit for the purpose of remapping a given address space into another.

NIR – National Internet Registry
A NIR primarily allocates address space to its members or constituents which are generally LIRs organized at a national level. NIRs mostly exist in the Asia Pacific region.

Nibble boundary
A bit is the smallest unit of data on a binary computer. A nibble is a collection of bits on a four-bit boundary (half-byte), that is, it takes four bits to represent a single binary code decimal (BCD) or hexadecimal digit (0-9, A, B, C, D, E, F in ASCII). When IPv6 addresses are represented in the DNS, the entire binary sequence is listed as hexidecimal characters. When listed in reverse, each hexadecimal character becomes a ‘nibble boundary’.

Non-portable
Non-portable addresses must be returned if the network changes upstream provider.

NRO – Number Resource Organization
The NRO is made up of the five Regional Internet Registries (RIRs), with the CEOs of each RIR forming its Executive Council (EC). Its main roles are to protect the unallocated number resource pool, to promote and protect the bottom-up policy development process, and to act as a focal point for Internet community input into the RIR system.
www.nro.net

NRO NC – Number Resource Organization (NRO) Number Council
The NRO NC is a group of 15 individuals selected by the five RIR communities (three from each region). It carries out the role of the Address Supporting Organization (ASO) Address Council (AC).
www.nro.net/about/number-council.html

Portable allocation
An RIR makes portable allocations to organizations such as LIRs (usually ISPs). That is, it distributes address space to IRs for the purpose of subsequent distribution by them.

rDNS – Reverse DNS
A database of information that translates an IP address to a domain or a host name.

RFC – Request For Comments
The name for an Internet standards-related specification. See https://www.ietf.org/rfc.html

Registrar
An entity that provides direct services to domain name registrants by processing name registrations.

Registry
An entity that runs the DNS authoritative server for a specific domain.

RPKI – Resource Public Key Infrastructure
The process of linking a digital “resource certificate” to an Internet number resource using Public Key Infrastructure (PKI) principles. This provides validatable proof that the associated resources are legitimately registered by the signing RIR. Resource certification is based on IETF standards, The primary goal is to make Internet routing more robust and secure. Described in RFC 6481-6493.

RESTful (REpresentational State Transfer)
A RESTful web service (also called a RESTful web API) is a web service implemented using HTTP and the principles of REST. See also WEIRDs.

Reverse Delegation
See Reverse DNS (rDNS).

RFC – Request for Comment
A document series of the IETF that focuses on concepts, networking, and Internet protocols. http://www.ietf.org/rfc.html

RIPE – Réseaux IP Européens
A collaborative forum open to all parties interested in wide area IP networks. The objective of RIPE is to ensure the administrative and technical coordination necessary to enable the operation of the Internet within the RIPE NCC service region. Although similar in name, the RIPE NCC and RIPE are separate entities.
www.ripe.net/ripe

RIPE NCC
The Regional Internet Registry (RIR) serving countries in Europe, the Middle East, and parts of Central Asia. http://www.ripe.net/

RIR – Regional Internet Registry
An organization overseeing the allocation and registration of Internet number resources within a particular region of the world. Resources include IP addresses (IPv4 and IPv6) and Autonomous System Numbers (ASNs). The Internet Assigned Numbers Authority (IANA) allocates these resources to each RIR. RIRs also maintain public databases of their registration information. There are currently five RIRs in operation namely AFRINIC, APNIC, ARIN, LACNIC, and RIPE NCC. (See also specific entry for each RIR).

Root
The root level is the top level of the Domain Name System, a hierarchical tree-like structure that maps domain names to IP addresses. Top-level domains include .com, .org, and country-level names such as .ca and .au.

Root Server
A DNS server pointing to all top-level domains.

Route Origin Authorization (ROA)
A ROA is a digitally signed object that was created using a resource certificate. It provides a means of verifying that an IP address block holder has authorized an AS to originate routes to one or more prefixes within the address block.

Routing Advertisements
Each router announces (advertises) a list of routes it can process, expressed as ranges of IP addresses for which it can provide routing service.

Routing Policy
A set of agreements on the traffic routed through multiple Internet Service Provider (ISP) networks.

Routing Registry
A public database of routing policy details, routes, and their aggregates, local topology between Autonomous Systems (AS) and network components, such as routers.

RPKI – Resource Public Key Infrastructure
A structure of digitally signed certificates which contain attestations regarding the right to use numeric Internet resources.

SANOG – South Asian Network Operators Group
A cooperational and educational forum bringing together operators in the South Asia region to discuss operational issues and technologies of interest.
www.sanog.org

SIG – Special Interest Group
SIGs are formal groups formed by the Internet community to discuss relevant issues, developments and to propose policies.

Sub-allocation
IP addresses are sub-allocated when they are distributed to an organization which then further assigns them to its own end users.

Subnet mask
The routing prefix of a designated IP address block.

TLD – Top-Level Domain
The most general part of a domain name, commonly identified as the letters following the final dot of its name (for example .com, .org, .net).

Transition Mechanisms
Methods of transitioning from IPv4 to IPv6. The IETF’s RFC 6180 “Guidelines for Using IPv6 Transition Mechanisms during IPv6 Deployment” offers an overview.
tools.ietf.org/rfc

ULAs – Unique Local Addresses
The IPv6 equivalent of IPv4 private address space. These addresses are reserved for local use in home and enterprise environments and are not public address space. These addresses might not be unique and there is no formal address registration. Packets with these addresses in the source or destination fields are not intended to be routed on the public Internet, but are intended to be routed within the enterprise or organization.

WEIRDS – Web Extensible Internet Registration Data Service
An IETF Working Group formed in 2012 whose purpose is to broaden the use of RESTful web services by achieving simple and common Uniform Resource Identifier (URI) patterns and responses amenable to all Internet number resource and domain name registries.

WG – Working Group
Working Groups are formal groups formed by the Internet community to discuss relevant issues, developments and to propose policies.

WHOIS
A query and response protocol that is widely used for querying databases that store the registered users or assignees of an Internet resource, such as a domain name, an IP address block, or an autonomous system, but is also used for a wider range of other information. The protocol stores and delivers database content in a human-readable format. See https://tools.ietf.org/html/rfc3912

WSIS – World Summit on Information Society
The WSIS took place in Geneva in December 2003 and in Tunis in November 2005. The objective of the first phase was to develop a statement of political will and establish the foundations for an Information Society for all. The objective of the second phase was to put the first phase planning into motion as well as to find solutions and reach agreements in the fields of Internet governance.
The WSIS has now ended. The Internet Governance Forum (IGF) was established based on some of the outcomes of the WSIS process.
www.itu.int/wsis

X.509 certificate
X.509 is a standard for digital certificates that uses PKI digital certificates in a hierarchical authentication structure. Described in RFC 5280.