DNS (Domain Name System)

system used on the Internet to find IP addresses matching domain names and vice versa.

E.164

standard defining phone numbers format and international numbering plan.

e164.arpa.

Internet domain dedicated to ENUM system; ENUM domain names for phone numbers are subdomains of this domain.

ENUM (E.164 NUmber Mapping)

system for storing information about IP services (Internet services) available to common phone numbers.

FQDN (Fully Qualified Domain Name)

full form of domain name which identifies a computer (server) on the Internet; IP address of this computer (server) could be obtained via DNS query.

IP phone

Phone, which connect the calls over IP networks (Internet) instead of public telephone network. IP phone could be common desk phone, mobile device or just a software application for a computer. List of all kinds of IP phones is on VoIP Wiki pages.

NAPTR (Naming Autority PoinTeR)

DNS record containing URIs of IP services available to the phone number (ENUM domain).

PSTN (Public Switched Telephone Network)

common telephone network, "classic" operator network.

SIP (Session Initiation Protocol)

communication protocol of Internet service used to carry voice in IP networks (Internet) - IP telephony protocol; identificator of the subscriber has similar format as email address.

Tier1

Tier is level of delegation in DNS tree. Tier0 is a top level domain (e164.arpa), from where subdomains are delefated to Tier1 registry. Tier1 is national domain (for Czech Rep. 0.2.4.e164.arpa) registry, from where subdomains are delegated to end users DNS servers or to Tier2 registries.

URI (Uniform Resource Indetifier)

unique identifier of sources on Internet, identifies type of service and its destination address; in ENUM is used to store the information how to connect with called party via SIP.

VoIP (Voice Over IP)

transfer of voice over IP network (Internet); voice services on the Internet - Internet telephony.