Glossary

It's probably impossible to get everybody to agree on terminology, but at least there should be a list somewhere

  • database: 1) (abstract) a formally structured collection of data; 2) (concrete) a system of computer software/hardware that implements and manages a database (abstract).

  • gTLD: "generic TLD". RFC1591 used the term "generic TLD" to refer to TLDs like .com, .net, .org, .mil, .gov, and .edu in opposition to the country code TLDs like .us, .fi, .it, and so on. The IAHC report particularized the term "generic TLD" to mean "a TLD that was 1) not a ccTLD, 2) with no registration restrictions on the type of entity that could register in it". The IAHC report resulted in the formation of the gTLD-MoU, which got far wider public exposure than RFC1591 ever did, and consequently most people who come into the debate are only familiar with the IAHC definition. In particular, the person who wrote the charter for WG-C was using the IAHC definition, not the RFC1591 definition. The term "open TLD" has some currency, but it includes ccTLDs.

  • gTLD registry: a registry for a particular gTLD ("the .com registry").

  • policy authority: an entity that has authority over policy. Different entities may have authority over different policy areas, and, since in general both the term "policy" and the term "authority" are very broad, combining the two gives a result almost guaranteed to cause confusion and argument. In the context of the gTLD discussions, a "Policy Authority" generally means an entity that sets high-level overall policy for a TLD. For open TLDs the default policy authority could be said to be ICANN.

  • Registrar: an entity with a direct contractual relationship with, and special access to, a registry, that inserts records on behalf of others.

  • Registration agent: Registrar. Nominet makes a distinction here that I don't fully understand -- if someone can explain that distinction I would like to know..

  • Registry: a database associating DNS information with some person, legal entity, operational entity, or other referrent. Note that we can speak of a registry in the abstract or in the concrete, as per the definition of "database" above. To emphasize the abstract meaning we may use the terms "registry database", or possibly "registry data".

  • Registry Administrator: An entity delegated administrative authority the registry. CORE was the administrator of the prototype CORE registry.

  • Registry Operator: the organization or business that operates a registry. This distinction is very important: NSI is the operator of the .com registry; Emergent was the operator of the prototype CORE registry.

  • Shared Registry: a registry that allows access from multiple distinct registrars.

  • Shared Registry System (SRS): the software that supports a shared registry. There are several extant shared registry systems -- NSI, CORE, and Nominet all have functioning SRSs.

  • Sponsor: an entity with policy authority over a TLD.

  • SRS: Shared Registry System

  • Thick vs Thin registry models: In a shared registry system there is a division of labor between the registrars and the registry. When Network Solutions (NSI) developed their particular shared registry system (SRS) they tried to minimize the functionality in the registry component and maximize the functionality in the registrar components: the registry keeps the domain name, the name server information, and a reference to the registrar that registered the name. The registrar keeps all other information. NSI called this the "thin registry model". Many people think this would have been better called the "anorexic registry model", because NSI eliminated keeping whois information from the responsibilities of the registry -- a function many people think must be centralized. Another label might be the "thick registrar model". The NOMINET model is the reverse, with extremely thin registrars (the only technical requirement for being a registrar in the NOMINET model is an email client that can run PGP). The CORE model is somewhere in between.

  • TLD: 1) One of the entries in the IANA-approved root zone. 2) The term may also be used in a generic technical sense to refer to an entry in any root zone. It is frequent practice to prefix the term "TLD" with a small letter to indicate some flavor of TLD, as in:

    • aTLD: ("alternate" TLD) An entry in some root zone which is visible on the public Internet when referenced as an IP address, but which is not included in the IANA root and is therefore not visible through the public DNS when referenced as a domain name.

    • cTLD: ("chartered" TLD) A TLD with a document ("charter") that defines registration and other policies for the TLD.

    • ccTLD: ("country code" TLD) A TLD that has its name derived from the ISO 3166 list of 2-letter region and country abbreviations.

    • gTLD: a TLD that has no enforced criteria for the entities that may register in it. This departs somewhat from the rfc1591 definition. A gTLD may have a charter; if the charter is enforced it would be better termed a "chartered TLD".

    • pTLD: ("private" TLD) An entry in some root zone other than the IANA-approved one. Most pTLDs are on private networks; a few are not.

  • whois: "whois" is a simple database system that manages public information for DNS registrants, and other data associated with DNS. It uses a simple client-server protocol; whois clients are available on most unix systems. There have been several attempts over the years to improve the protocol -- there are RFCs for other versions of whois, but they have never reached wide acceptance or use.

  • whois data: Information kept in the whois database. The most important information kept in whois for a domain name are 1) the "registrant" information -- the name and legal address of the registrant, 2) addresses of the administrative, technical (zone), and billing contacts, 3) name server information, and 4) update and creation dates for the record.

  • zone: "Zone" is a technical term in DNS with subtleties that are difficult to explain in a few words. However, for our purposes we may think of it as the information that defines a part of the DNS hiearchy that share a common prefix, and that does not contain information for lower level zones. Zone entries can either be direct information (eg, the IP address of a host in the zone), or information that dscribes the hierarchy of zones (the "glue" records that connect zones). For example, the .com zone contains several million entries, most of which reference a lower level zone (subzone), ie, mostly glue. aol.com is a subzone of the .com zone; it contains some 16 million entries, most of which are direct data.