Networking & Internet Terms

An Internet Protocol (IP) address is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. It serves two main functions: host or network interface identification and location addressing.

The Internet protocol suite, commonly known as TCP/IP, is the set of communication protocols used in the Internet and similar computer networks. It provides end-to-end data communication specifying how data should be packetized, addressed, transmitted, routed, and received.

Hypertext Transfer Protocol Secure (HTTPS) is an extension of the Hypertext Transfer Protocol (HTTP). It is used for secure communication over a computer network, and is widely used on the Internet. In HTTPS, the communication protocol is encrypted using Transport Layer Security (TLS) or, formerly, its predecessor, Secure Sockets Layer (SSL).

A Uniform Resource Locator (URL), colloquially termed a web address, is a reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it.

A domain name is an identification string that defines a realm of administrative autonomy, authority or control within the Internet. Domain names are used in various networking contexts and for application-specific naming and addressing purposes.

A router is a networking device that forwards data packets between computer networks. Routers perform the traffic directing functions on the Internet. A data packet is typically forwarded from one router to another through the networks that constitute an internetwork until it reaches its destination node.

A network switch is a networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device. It operates at the data link layer (Layer 2) of the OSI model.

A Local Area Network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building.

A Wide Area Network (WAN) is a telecommunications network that extends over a large geographic area. WANs are used to connect smaller networks, such as LANs or metro area networks.

Wi-Fi is a family of wireless network protocols, based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access. It allows nearby digital devices to exchange data by radio waves.

A packet is a small unit of data that is routed between an origin and a destination on the Internet or any other packet-switched network. Data sent over computer networks is broken down into packets.

In telecommunications, a communication protocol is a system of rules that allow two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchronization of communication and possible error recovery methods.

The Open Systems Interconnection (OSI) model is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to their underlying internal structure and technology. Its goal is the interoperability of diverse communication systems with standard protocols. The model partitions a communication system into seven abstract layers.

The Transmission Control Protocol (TCP) is one of the main protocols of the Internet protocol suite. It provides reliable, ordered, and error-checked delivery of a stream of octets (bytes) between applications running on hosts communicating via an IP network.

The User Datagram Protocol (UDP) is a communication protocol used across the Internet for time-sensitive transmissions such as video playback or DNS lookups. It is a simpler, connectionless protocol that does not provide reliability, ordering, or error checking.

In computer networking, a port is a communication endpoint. At the software level, within an operating system, a port is a logical construct that identifies a specific process or a type of network service. Ports are identified for each protocol and address combination by 16-bit numbers.

A network socket is an internal endpoint for sending or receiving data at a single node in a computer network. Concretely, it is a representation of this endpoint in networking software. It is a combination of an IP address and a port number.

Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 addresses are 32-bit numbers.

Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP). It is designed to replace IPv4. IPv6 addresses are 128-bit numbers.

Network Address Translation (NAT) is a method of remapping an IP address space into another by modifying network address information in the IP header of packets while they are in transit across a traffic routing device.

A Media Access Control (MAC) address is a unique identifier assigned to a network interface controller (NIC) for use as a network address in communications within a network segment. It is used at the data link layer (Layer 2) of the OSI model.

An Internet Service Provider (ISP) is an organization that provides services for accessing, using, or participating in the Internet. ISPs may be organized in various forms, such as commercial, community-owned, non-profit, or otherwise privately owned.

The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on Internet Protocol networks for automatically assigning IP addresses and other communication parameters to devices connected to the network.

A subnet mask is a 32-bit number that masks an IP address and divides the IP address into a network address and a host address. The subnet mask is made by setting network bits to all "1"s and setting host bits to all "0"s.

In a computer network, a gateway is a node that serves as a connection point from one network to another. It is the device that routes traffic from a local network to devices on other networks.

Ping is a computer network administration software utility used to test the reachability of a host on an Internet Protocol (IP) network. It measures the round-trip time for messages sent from the originating host to a destination computer that are echoed back by the destination.

Traceroute is a computer network diagnostic tool for displaying the path (route) and measuring transit delays of packets across an Internet Protocol (IP) network. The history of the route is recorded as the round-trip times of the packets received from each successive host (remote node) in the route.

The Internet Protocol (IP) is the principal communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet.

A wireless access point (WAP) is a networking hardware device that allows other Wi-Fi devices to connect to a wired network. The WAP usually connects to a router as a standalone device, but it can also be an integral component of the router itself.

A network hub is a simple, older networking device that connects multiple computers or other network devices together. It operates at the physical layer (Layer 1) of the OSI model. When it receives a data packet, it broadcasts that packet to every other port on the hub.

The Internet Control Message Protocol (ICMP) is a supporting protocol in the Internet protocol suite. It is used by network devices, including routers, to send error messages and operational information indicating, for example, that a requested service is not available or that a host or router could not be reached.

The Internet Message Access Protocol (IMAP) is an Internet standard protocol used by email clients to retrieve email messages from a mail server over a TCP/IP connection. IMAP allows for the management of email directly on the server.

The Post Office Protocol version 3 (POP3) is an application-layer Internet standard protocol used by e-mail clients to retrieve e-mail from a mail server. In its default mode, it downloads emails to the client and then deletes them from the server.

The Simple Mail Transfer Protocol (SMTP) is a communication protocol for electronic mail transmission. As its name indicates, SMTP is a push protocol and is used to send the e-mail, whereas POP3 or IMAP are used to retrieve it from the mail server.

The Address Resolution Protocol (ARP) is a communication protocol used for discovering the link layer address, such as a MAC address, associated with a given internet layer address, typically an IPv4 address. This mapping is a critical function in the Internet protocol suite.

Classless Inter-Domain Routing (CIDR) is a method for allocating IP addresses and for IP routing. It replaced the previous system of addressing based on classes A, B, and C. Its goal was to slow the growth of routing tables on routers across the Internet, and to help slow the rapid exhaustion of IPv4 addresses.

Telnet is an application protocol used on the Internet or local area networks to provide a bidirectional interactive text-oriented communication facility using a virtual terminal connection. User data is interspersed in-band with Telnet control information in an 8-bit byte oriented data connection over the Transmission Control Protocol (TCP).

Network topology is the arrangement of the elements (links, nodes, etc.) of a communication network. It can be used to define or describe the arrangement of various types of telecommunication networks, including command and control radio networks, industrial fieldbusses and computer networks.

Broadband is a wide bandwidth data transmission with an ability to simultaneously transport multiple signals and traffic types. In the context of Internet access, broadband is used to mean any high-speed Internet access that is always on and faster than traditional dial-up access.

HyperText Markup Language (HTML) is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScript.

Cascading Style Sheets (CSS) is a style sheet language used for describing the presentation of a document written in a markup language such as HTML. CSS is a cornerstone technology of the World Wide Web, alongside HTML and JavaScript.

JavaScript, often abbreviated as JS, is a programming language that conforms to the ECMAScript specification. It is high-level, often just-in-time compiled, and multi-paradigm. It has curly-bracket syntax, dynamic typing, prototype-based object-orientation, and first-class functions.

A Uniform Resource Identifier (URI) is a unique sequence of characters that identifies a logical or physical resource used by web technologies. URIs may be used to identify anything, including real-world objects, such as people and places, concepts, or information resources such as web pages and books.

In networking, a hop is one portion of the path between a source and destination. When data is passed from one network segment to the next, such as from one router to another, it is considered a hop.

Time to Live (TTL) is a mechanism that limits the lifespan or lifetime of data in a computer or network. In an IP packet, TTL is an 8-bit field. Each router that forwards the packet decrements the TTL value by one. If the TTL value reaches zero, the router discards the packet.

The Border Gateway Protocol (BGP) is a standardized exterior gateway protocol designed to exchange routing and reachability information among autonomous systems (AS) on the Internet. It is the protocol that makes the internet work.

Open Shortest Path First (OSPF) is a routing protocol for Internet Protocol (IP) networks. It uses a link state routing (LSR) algorithm and falls into the group of interior gateway protocols (IGPs), operating within a single autonomous system (AS).

Routing is the process of selecting a path for traffic in a network or between or across multiple networks. Broadly, routing is performed in many types of networks, including circuit-switched networks, such as the public switched telephone network (PSTN), and computer networks, such as the Internet.

The World Wide Web (WWW), commonly known as the Web, is an information system where documents and other web resources are identified by Uniform Resource Locators (URLs), which may be interlinked by hyperlinks, and are accessible over the Internet.

The Internet is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a network of networks that consists of private, public, academic, business, and government networks of local to global scope.

The SSH File Transfer Protocol (also Secure File Transfer Protocol, or SFTP) is a network protocol that provides file access, file transfer, and file management over any reliable data stream. It was designed by the Internet Engineering Task Force (IETF) as an extension of the Secure Shell protocol (SSH) version 2.0 to provide secure file transfer capabilities.

FTPS (also known as FTP-ES, FTP-SSL, and FTP Secure) is an extension to the commonly used File Transfer Protocol (FTP) that adds support for the Transport Layer Security (TLS) and, formerly, the Secure Sockets Layer (SSL) cryptographic protocols.

The Network Time Protocol (NTP) is a networking protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks. It is one of the oldest Internet protocols in continuous use.