In the Internet, the exact network location of a computer or a node. Addresses can be numerical or name.
anycast
A method, developed for IPv6, of sending a datagram or packet to a single address with more than one interface. The packet is usually sent to the ‘‘nearest’' node in a group of nodes, as determined by the router. Compare to multicast and unicast.
authentication
The process of verifying that the person or machine trying to gain access to a system or site is actually as claimed. Usually verified by a password; however, since passwords can be guessed or discovered, a system that requires an encrypted password and a key to decrypt it are becoming popular.
Classless Inter-Domain Routing Protocol
Also CIDR. A policy that basically eliminates the IPv4 address class structure (A, B, and C). This allows, for example, a single network number to be assigned from a block of class C addresses to a requesting organization.
datagram
Term used in IPv4. The format for a packet of data sent on the Internet to a specific destination address. Specifies standards for the header information. In IPv6, datagrams are known as packets.
encryption
Conversion of human-readable data (plaintext) into encoded data (ciphertext) that can be decoded only with a specific key.
flow, flow label
A flow is a sequence of transmitted packets for which the source wants special handling by intervening routers. It has a unique identification of a source address and a nonzero 24-bit flow label.
gateway
See router.
header
The information at the beginning of a message being transmitted. Includes the source and destination addresses, routing, and other information.
host, host computer
Any end-user computer, such as a personal computer or workstation that is part of a local area network, or any other system that connects to a network and functions as the endpoint of a data transfer on the Internet.
Internet
The connection of the uncountable, dissimilar networks of computers throughout the world using TCP/IP to exchange data. Differentiate this from internet, with a lowercase i, which is a local network that shares a common communications protocol.
Internet Engineering Task Force
Also IETF. An international group of network designers, operators, vendors, and researchers, closely aligned to the Internet Architecture Board and chartered to work on the design and engineering of TCP/IP and the global Internet. The IETF is divided into groups or areas, each with a manager. Open to any interested individual.
Internet Protocol
The protocol or standard at the network level of the Internet that defines the packets of information and routing them to remote nodes, and the method of addressing remote computers and routing packets to remote hosts.
Internet Service Provider
Businesses that provide subscription services, such as online information retrieval software, bulletin boards, electronic mail, and so on to users for a fee.
IP
See Internet Protocol.
IPv4 and IPv6
IPv4 is the current version of the Internet Protocol; IPv6, which is being developed and tested now, will be the next version.
Maximum Transmission Units
The largest amount of data that can be transferred across a network; size is determined by the network hardware.
multicast
Method of transmitting messages to a selected subset of all the hosts that can receive the messages.
packet
In the IPv6, the name for datagram. The units of data a transmission is broken into so it can be sent in the most efficient and quick manner across the network.
protocol
A standard or set of rules that govern how something works, in this case, the Internet.
router
An internet device that connects two networks, either local or wide area networks, that use identical protocols. Passes, or routes, data being sent between the two networks.
routing table
A table of information on each machine that stores information about possible destination addresses and how to reach them. Used by IP to decide where to send a datagram or packet.
Transmission Control Protocol
The protocol at the Internet’s transport layer that governs the transmission of datagrams or packets by providing reliable, full-duplex, stream service to application protocols, especially IP. Provides reliable connection-oriented service by requiring that the sender and receiver exchange control information, or establish a connection before transmission can occur. Contrast to User Datagram Protocol.
unicast
The method of sending a packet or datagram to a single address. Compare to anycast and multicast.
User Datagram Protocol
An unreliable, connectionless protocol suite that manages the transport of data. Often used with the Internet Protocol for transmissions that will normally create an automatic response when received. Contrast to Transmission Control Protocol.