Networking Definitions

This glossary explains the meaning of key words and phrases that information technology (IT) and business professionals use when discussing networking and related software products. You can find additional definitions by visiting WhatIs.com or using the search box below.

  • N

    Network Address Translation (NAT)

    A Network Address Translation (NAT) is the process of mapping an internet protocol (IP) address to another by changing the header of IP packets while in transit via a router.

  • network analytics

    Network analytics is the application of big data principles and tools to the data used to manage and secure data networks.

  • network analyzer (protocol analyzer or packet analyzer)

    A network analyzer -- also called a network protocol analyzer or packet analyzer -- is a software application, dedicated appliance or feature set within a network component used in network performance troubleshooting or to enhance protection against malicious activity within a corporate network.

  • Network as a Service (NaaS)

    Network as a service (NaaS) is a business model for delivering enterprise-wide area network services virtually on a subscription basis.

  • network automation

    Network automation is a methodology in which software automatically configures, provisions, manages and tests network devices.

  • network configuration management (NCM)

    Network configuration management is the process of organizing and maintaining information about all of the components in a computer network.

  • network downtime

    Network downtime refers to inaccessibility to part or all of a network due to the failure of hardware, software or some combination of the two.

  • network engineer

    A network engineer is a technology professional who has the necessary skills to plan, implement and oversee the computer networks that support in-house voice, data, video and wireless network services.

  • network fabric

    Network fabric is an industry term that describes a network topology in which devices pass data to each other through interconnecting switches.

  • network functions virtualization (NFV)

    Network functions virtualization (NFV) is a network architecture model designed to virtualize network services that have traditionally run on proprietary, dedicated network appliances.

  • network hub

    A network hub is a node that broadcasts data to every computer or Ethernet-based device connected to it.

  • network interface card (NIC)

    A network interface card (NIC) is a hardware component, typically a circuit board or chip, which is installed on a computer so it can connect to a network.

  • Network layer

    Located at Layer 3 of the Open Systems Interconnection (OSI) communications model, the primary function of the network layer is to move data into and through other networks.

  • network management

    A cornerstone of all computing is the ability to connect one machine, system or device to another -- enabling what is known as a computer network.

  • network management system

    A network management system (NMS) is an application or set of applications that lets network engineers manage a network's independent components inside a bigger network management framework and performs several key functions.

  • network monitoring

    Network monitoring, also frequently called network management, is the practice of consistently overseeing a computer network for any failures or deficiencies to ensure continued network performance.

  • network node

    A computer network is a system of computers and computing devices that are connected via communication links.

  • network operating system (NOS)

    A network operating system (NOS) is a computer operating system (OS) that is designed primarily to support workstations, personal computers and, in some instances, older terminals that are connected on a local area network (LAN).

  • network operations center (NOC)

    A network operations center (NOC) is a centralized place from which enterprise information technology (IT) administrators -- either internal or third party -- supervise, monitor and maintain a telecommunications network.

  • network packet

    A network packet is a basic unit of data that's grouped together and transferred over a computer network, typically a packet-switched network, such as the internet.

  • network performance monitoring

    Network performance monitoring is a process of measuring and monitoring the quality of service of a network to understand if it is properly operating.

  • network protocol

    A network protocol is a set of established rules that dictate how to format, transmit and receive data so that computer network devices -- from servers and routers to endpoints -- can communicate, regardless of the differences in their underlying infrastructures, designs or standards.

  • network scanning

    Network scanning is a procedure for identifying active devices on a network by employing a feature or features in the network protocol to signal devices and await a response.

  • network security

    Network security encompasses all the steps taken to protect the integrity of a computer network and the data within it.

  • network segmentation

    Network segmentation is a networking architectural design that divides a network into multiple segments (subnets) with each functioning as a smaller, individual network.

  • network service provider (NSP)

    A network service provider (NSP) is a company that owns, operates and sells access to internet backbone infrastructure and services.

  • network switch

    A network switch is a hardware device that channels incoming data from multiple input ports to a specific output port that will take it toward its intended destination.

  • network tap

    A network tap is an external monitoring device that mirrors the traffic that passes between two network nodes. A tap (test access point) is a hardware device inserted at a specific point in the network to monitor data.

  • Network Time Protocol (NTP)

    Network Time Protocol (NTP) is an internet protocol used to synchronize with computer clock time sources in a network.

  • network topology

    A network topology is the physical and logical arrangement of nodes and connections in a network.

  • network traffic

    Network traffic is the amount of data that moves across a network during any given time.

  • network visibility

    Network visibility is an awareness of the components and data within an enterprise computer network.

  • Networking (computer)

    Networking, also known as computer networking, is the practice of transporting and exchanging data between nodes over a shared medium in an information system.

  • Next Hop Resolution Protocol (NHRP)

    Next Hop Resolution Protocol (NHRP) is an automated configuration technology that routes data on a distributed network by discovering the best routing path between endpoints.

  • NFV MANO (network functions virtualization management and orchestration)

    NFV MANO (network functions virtualization management and orchestration), also called MANO, is an architectural framework for managing and orchestrating virtualized network functions (VNFs) and other software components.

  • NFVi (network functions virtualization infrastructure)

    NFVi (network functions virtualization infrastructure) encompasses all of the networking hardware and software needed to support and connect virtual network functions in carrier networks.

  • NIS (Network Information System)

    NIS (Network Information System) is a network naming and administration system for smaller networks that was developed by Sun Microsystems.

  • nslookup

    nslookup is the name of a program that lets an Internet server administrator or any computer user enter a host name (for example, "whatis.com") and find out the corresponding IP address or domain name system (DNS) record.

  • NVGRE (Network Virtualization using Generic Routing Encapsulation)

    NVGRE (Network Virtualization using Generic Routing Encapsulation) is a network virtualization method that uses encapsulation to create large numbers of virtual LANs (VLANs) for subnets that can extend across dispersed data centers and Layers 2 and 3.

  • What is NetOps? Everything you need to know

    NetOps, also referred to as NetOps 2.0 and NetDevOps, is an approach to networking operations that uses DevOps tools and techniques to make network changes more efficiently and effectively than in the past.

  • What is network virtualization? Everything you need to know

    Network virtualization is a method of combining the available resources in a network to consolidate multiple physical networks, divide a network into segments or create software networks between VMs.

  • O

    OFDMA (orthogonal frequency-division multiple access)

    Orthogonal frequency-division multiple access (OFDMA) is a feature of Wi-Fi 6 (802.11ax) that allows access points to serve multiple clients at the same time.

  • offline

    Offline is the condition of being capable of but currently not connected to a network of computers or other devices.

  • ONOS (Open Network Operating System)

    ONOS (Open Network Operating System) is an operating system (OS) designed for network service providers to help build carrier-grade software-defined networks architected for high scalability, availability and performance

  • open networking

    Open networking describes a network that uses open standards and commodity hardware.

  • operational support system (OSS)

    An operational support system (OSS) is a set of programs that help a communications service provider monitor, control, analyze and manage a telephone or computer network.

  • optical line terminal (OLT)

    An optical line terminal (OLT) is a device that is located at the service provider's central office and is the endpoint of a passive optical network (PON).

  • optoisolator (optical coupler or optocoupler)

    An optoisolator (also known as an optical coupler, photocoupler, optocoupler) is a semiconductor device that transfers an electrical signal between isolated circuits using light.

  • orthogonal frequency-division multiplexing (OFDM)

    Orthogonal frequency-division multiplexing (OFDM) is a method of data transmission where a single information stream is split among several closely spaced narrowband subchannel frequencies instead of a single wideband channel frequency.

  • OSGi (Open Service Gateway Initiative)

    The OSGi (Open Service Gateway Initiative) specification is a Java framework for developing and deploying modular software programs and libraries.

  • OSI model (Open Systems Interconnection)

    OSI (Open Systems Interconnection) is a reference model for how applications communicate over a network.

  • OSPF (Open Shortest Path First)

    The OSPF router protocol is used to find the best path for packets as they pass through a set of connected networks. OSPF is one of several Interior Gateway Protocols that replaces the Routing Information Protocol (RIP), an older routing protocol that is installed in many of today's corporate networks.

  • overlay network

    An overlay network is a virtual or logical network that is created on top of an existing physical network.

  • OVSDB (Open vSwitch Database Management Protocol)

    The Open vSwitch Database Management Protocol (OVSDB) is an OpenFlow configuration protocol that is designed to manage Open vSwitch implementations.

  • P

    packet filtering

    On the Internet, packet filtering is the process of passing or blocking packets at a network interface based on source and destination addresses, ports, or protocols.

  • packet loss

    Packet loss is when one or more transmitted data packets fail to arrive at their destination.

  • passive optical network (PON)

    A passive optical network (PON) is a system commonly used by telecommunications network providers that brings fiber optic cabling and signals all or most of the way to the end user.

  • patch panel

    A patch panel in a local area network (LAN) is a mounted hardware assembly that contains ports that are used to connect and manage incoming and outgoing LAN cables.

  • peer-to-peer (P2P)

    Peer-to-peer (P2P) is a decentralized communications model in which each party has the same capabilities and either party can initiate a communication session.

  • phase-locked loop (PLL)

    A phase-locked loop (PLL) is an electronic circuit with a voltage or voltage-driven oscillator that constantly adjusts to match the frequency of an input signal.

  • physical layer

    Located at the lowest layer of the Open Systems Interconnection (OSI) communications model, the physical layer's function is to transport data using electrical, mechanical or procedural interfaces.

  • ping

    A ping (Packet Internet or Inter-Network Groper) is a basic internet program that enables a user to test and verify if a particular destination Internet Protocol (IP) address exists and can accept requests in computer network administration.

  • ping sweep (ICMP sweep)

    A ping sweep (also known as an ICMP sweep) is a basic network scanning technique used to determine which of a range of IP addresses map to live hosts (computers).

  • Plain Old Telephone Service (POTS)

    Plain Old Telephone Service (POTS) refers to the traditional, analog voice transmission phone system implemented over physical copper wires (twisted pair).

  • point-of-presence (POP)

    On the Internet, a point-of-presence (POP) is an access point from one place to the rest of the Internet.

  • Point-to-Point Protocol (PPP)

    Point-to-Point Protocol (PPP) refers to a suite of computer communication protocols that provide a standard way to transport multiprotocol data over point-to-point links.

  • Point-to-Point Protocol over Ethernet (PPPoE)

    Point-to-Point Protocol over Ethernet (PPPoE) is a network protocol that facilitates communication between network endpoints.

  • poison reverse

    In a computer network that uses the Routing Information Protocol (RIP) or other distance vector routing protocol, poison reverse is a loop avoidance process.

  • port

    A port in computing has three main uses, each as a type of receptacle in networking, computer hardware and software.

  • port 80

    On a Web server or Hypertext Transfer Protocol daemon, port 80 is the port that the server "listens to" or expects to receive from a Web client, assuming that the default was taken when the server was configured or set up.

  • Port Address Translation (PAT)

    Port Address Translation (PAT), is an extension to network address translation (NAT) that permits multiple devices on a local area network (LAN) to be mapped to a single public IP address. The goal of PAT is to conserve IP addresses.

  • port number

    Port number is a way to identify a specific process to which an internet or other network message is to be forwarded when it arrives at a server.

  • Power over Ethernet (PoE)

    Power over Ethernet (PoE) is a technology for implementing wired Ethernet local area networks (LANs) that enables the electrical current necessary for operating each device to be carried by Ethernet data cables instead of standard electrical power cords and wiring.

  • preboot execution environment (PXE)

    Preboot execution environment (PXE), pronounced pixie, is a set of standards that enables a computer to load an operating system (OS) over a network connection.

  • presentation layer

    Residing at Layer 6 of the Open Systems Interconnection (OSI) communications model, the presentation layer ensures that the communications that pass through it are in the appropriate form for the recipient application.

  • private 5G

    Private 5G is wireless network technology that delivers cellular connectivity for private network use cases, such as private businesses, third-party providers and municipalities.

  • programmable network (network programmability)

    A programmable network is one in which the behavior of network devices and flow control is handled by software that operates independently of network hardware.

  • propagation delay

    Propagation delay is the amount of time required for a signal to be received after it has been sent; it is caused by the time it takes for the signal to travel through a medium.

  • protocol data unit (PDU)

    In networking, a protocol data unit is the basic unit of exchange between entities that communicate using a specified networking protocol.

  • PSTN (public switched telephone network)

    The public switched telephone network, or PSTN, is the world's collection of interconnected voice-oriented public telephone networks.

  • Q

    QAM (quadrature amplitude modulation)

    QAM (quadrature amplitude modulation) is a method of combining two amplitude modulation (AM) signals into a single channel.

  • queries-per-second (QPS)

    Queries-per-second (QPS) (or the query-per-second rate) is a measure of how much traffic a particular query server is handling at a given time.

  • R

    radio access network (RAN)

    A radio access network (RAN) is a major component of a wireless telecommunications system that connects individual devices to other parts of a network through a radio link.

  • radio frequency (RF, rf)

    Radio frequency (RF) is a measurement representing the oscillation rate of electromagnetic radiation spectrum, or electromagnetic radio waves, from frequencies ranging from 300 GHz to as low as 9 kHz.

  • Real-time Transport Protocol (RTP)

    Real-time Transport Protocol (RTP) is a network standard designed for transmitting audio or video data that is optimized for consistent delivery of live data.

  • repeater

    In digital communication systems, a repeater is a device that receives a digital signal on an electromagnetic or optical transmission medium and regenerates the signal along the next leg of the medium.

  • Reverse Address Resolution Protocol (RARP)

    Reverse Address Resolution Protocol (RARP) is a protocol a physical machine in a local area network (LAN) can use to request its IP address.

  • ROADM (reconfigurable optical add-drop multiplexer)

    An ROADM (reconfigurable optical add-drop multiplexer) is a device that can add, block, pass or redirect modulated infrared (IR) and visible light beams of various wavelengths in a fiber optic network. ... (Continued)

  • route summarization (route aggregation)

    Route summarization -- also known as route aggregation -- is a method to minimize the number of routing tables in an Internet Protocol (IP) network.

  • router

    A router is a physical or virtual appliance that passes information between two or more packet-switched computer networks.

  • Routing Information Protocol (RIP)

    Routing Information Protocol (RIP) is a distance vector protocol that uses hop count as its primary metric.

  • routing table

    A routing table is a set of rules, often viewed in table format, that's used to determine where data packets traveling over an Internet Protocol (IP) network will be directed.

  • RS-232C

    RS-232C is a long-established standard ("C" is the current version) that describes the physical interface and protocol for relatively low-speed serial data communication between computers and related devices.

  • runbook

    Runbooks are a set of standardized written procedures for completing repetitive IT processes within a company.

  • S

    SD-branch

    SD-branch is a single, automated, centrally managed software-centric platform that replaces or supplements an existing branch network architecture.

  • SD-WAN (software-defined WAN)

    Software-defined WAN (SD-WAN) is technology that uses software-defined networking (SDN) concepts to distribute network traffic across a wide area network (WAN).

  • SDN controller (software-defined networking controller)

    An SDN controller is an application in a software-defined networking (SDN) architecture that manages flow control for improved network management and application performance.

  • Secure Access Service Edge (SASE)

    Secure Access Service Edge, also known as SASE -- pronounced 'sassy' -- is a cloud architecture that bundles network and security solutions together and delivers them as a unified cloud service.

  • Seebeck effect

    The Seebeck effect is a phenomenon in which a temperature difference between two dissimilar electrical conductors or semiconductors produces a voltage difference between the two substances.

  • serial digital interface (SDI)

    Serial digital interface (SDI) is a standard for digital video and audio transmission over coaxial or fiber optic cabling.

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