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.

  • L

    local access and transport area (LATA)

    LATA (local access and transport area) is a term in the U.S. for a geographic area covered by one or more local telephone companies, which are legally referred to as local exchange carriers (LECs).

  • local area network (LAN)

    A local area network (LAN) is a group of computers and peripheral devices that share a common communications line or wireless link to a server within a distinct geographic area.

  • local loop

    In telephony, a local loop is the wired connection from a telephone company's central office in a locality to its customers' telephones at homes and businesses.

  • location-based service (LBS)

    A location-based service (LBS) is a software application for a mobile device that requires knowledge about where the mobile device is located.

  • logical network

    A logical network is one that appears to the user as a single, separate entity although it might in fact be either just a part of a larger network or an entity connecting multiple networks. A logical network is defined by its IP addressing scheme.

  • loopback test

    A loopback test is a test in which a signal in sent from a communications device and returned (looped back) to it as a way to determine whether the device is working right or as a way to pin down a failing node in a network.

  • loose coupling

    Loose coupling is a method of interconnecting the components in a system or network so that those components, also called elements, depend on each other to the least extent practicable... (Continued)

  • M

    MAC address (Media Access Control address)

    In a local area network (LAN) or other network, the MAC (Media Access Control) address is your computer's unique hardware number.

  • managed network services

    Managed network services are networking applications, functions and services that enterprises outsource to be remotely operated, monitored and maintained by a managed service provider (MSP).

  • Manchester encoding

    In data transmission, Manchester encoding is a form of digital encoding in which data bits are represented by transitions from one logical state to the other.

  • maximum segment size (MSS)

    The maximum segment size (MSS) is the largest amount of data, specified in bytes, that a computer or communications device can handle in a single, unfragmented piece.

  • maximum transmission unit (MTU)

    The maximum transmission unit (MTU) is the largest size frame or packet -- in bytes or octets (eight-bit bytes) -- that can be transmitted across a data link.

  • MDI/MDIX (medium-dependent interface/MDI crossover)

    MDI/MDIX is a type of Ethernet port connection that uses twisted-pair cabling to link two networked devices.

  • media access management

    In the Open Systems Interconnection (OSI) communication reference model, media access management is performed by the Media Access Control (MAC) sublayer of the Data-Link Layer.

  • megabits per second (Mbps)

    Megabits per second (Mbps) are units of measurement for network bandwidth and throughput. It is used to show how fast a network or internet connection is.

  • megahertz (MHz)

    The megahertz, abbreviated MHz, is a unit of alternating current (AC) or electromagnetic (EM) wave frequency equal to one million hertz (1,000,000 Hz).

  • metropolitan area network (MAN)

    A metropolitan area network (MAN) is a computer network that is larger than a single building local area network (LAN) but is located in a single geographic area that is smaller than a wide area network (WAN).

  • MHz

    The megahertz, abbreviated MHz, is a unit of alternating current (AC) or electromagnetic (EM) wave frequency equal to one million hertz (1,000,000 Hz).

  • microsegmentation

    Microsegmentation is a technique used to divide a network into logical and secure units through the application of policies that dictate how data and applications are accessed and controlled.

  • Microsoft Network Access Protection (NAP)

    Network access protection (NAP), introduced with Windows Server 2008, is Microsoft’s approach to controlling access to a network based on a determination of each device’s health.

  • millimeter wave (MM wave)

    Millimeter wave (MM wave), also known as millimeter band, is the band of spectrum with wavelengths between 10 millimeters (30 GHz) and 1 millimeter (300 GHz).

  • Mininet

    Mininet is a software emulator for prototyping a large network on a single machine. 

  • modem error-correcting protocols

    The protocols that modems agree on and use for checking and correcting transmission errors have evolved toward accuracy, speed, and efficiency since 1978 when the Xmodem protocol became a de facto standard.

  • modem lights (AA)

    This page provides a description of the abbreviations and meanings of each of the lights that describe the "handshaking" between a computer modem and the UART chip in a computer.

  • modulation

    Modulation is the process of converting data into radio waves by adding information to an electronic or optical carrier signal.

  • Morse code

    Morse code is a method of sending text messages by keying in a series of electronic pulses, usually represented as a short pulse (called a "dot") and a long pulse (a "dash").

  • MPLS-TP (MPLS Transport Profile)

    The Multiprotocol Label Switching Transport Profile (MPLS-TP) is a protocol extension of MPLS designed to speed up and shape network traffic in operator transport networks.

  • multi-user MIMO

    Multi-user MIMO (MU-MIMO) is a wireless communication technology that uses multiple antennas to improve communication by creating multiple connections to the same device at the same time

  • multicast

    Multicast is communication between a single sender and multiple receivers on a network.

  • multihomed

    Multihomed describes a computer host that has multiple IP addresses to connected networks.

  • multiplexing

    Multiplexing, or muxing, is a way of sending multiple signals or streams of information over a communications link at the same time in the form of a single, complex signal.

  • Multiprotocol Label Switching (MPLS)

    Multiprotocol Label Switching (MPLS) is a protocol-agnostic routing technique designed to speed up and shape traffic flows across enterprise wide area and service provider networks.

  • mutex (mutual exclusion object)

    In computer programming, a mutex (mutual exclusion object) is a program object that is created so that multiple program thread can take turns sharing the same resource, such as access to a file.

  • mux

    In communication transmission systems, mux (pronounce muks, sometimes spelled "MUX") is an abbreviation for multiplexing, a device that sends multiple signals on a carrier channel at the same time in the form of a single, complex signal to another device that recovers the separate signals at the receiving end.

  • N

    NACK (NAK, negative acknowledgment, not acknowledged)

    NACK, or NAK, an abbreviation for negative acknowledgment or not acknowledged, is a signal used by computers or other devices to indicate that data transmitted over a network was received with errors or was otherwise unreadable.

  • NBAR (Network Based Application Recognition)

    Network Based Application Recognition (NBAR) is a mechanism that classifies and regulates bandwidth for network applications to ensure that available resources are utilized as efficiently as possible. Cisco Systems developed NBAR as part of its Content Networking platform for implementing intelligent network services... (Continued)

  • NBASE-T Ethernet

    NBASE-T Ethernet is an IEEE standard and Ethernet-signaling technology that allows existing twisted-pair copper cabling to exceed the cable's specified limit of 1 Gbps for distances of up to 100 meters.

  • NBMA (non-broadcast multiple access)

    Non-broadcast multiple access (NBMA) is one of four network types in the Open Shortest Path First (OSPF) communications protocol.

  • near-end crosstalk (NEXT)

    Near-end crosstalk (NEXT) is an error condition that can occur when connectors are attached to twisted pair cabling.

  • Nessus

    Nessus is an open-source network vulnerability scanner that uses the Common Vulnerabilities and Exposures architecture for easy cross-linking between compliant security tools.

  • net neutrality

    Net neutrality is the concept of an open, equal internet for everyone, regardless of content consumed or the device, application or platform used.

  • NetBIOS (Network Basic Input/Output System)

    NetBIOS (Network Basic Input/Output System) is a network service that enables applications on different computers to communicate with each other across a local area network (LAN).

  • NETCONF

    NETCONF is an IETF network management protocol that provides an administrator or network engineer with a secure way to configure a firewall, router, switch or other network device.

  • NetOps

    NetOps, also referred to as NetOps 2.0, is a networking approach that encompasses the use of DevOps tools, methods and techniques to create an agile, scalable and programmable infrastructure capable of delivering business-critical applications and services rapidly and efficiently.

  • NetScaler (SDX)

    Citrix NetScaler SDX is a service delivery networking platform for enterprise and cloud datacenters. NetScaler SDX supports multiple NetScaler instances on a single hardware appliance.

  • network access control (NAC)

    Network access control (NAC), also called network admission control, is a method to bolster the security, visibility and access management of a proprietary network.

  • 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 management and security of 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 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 an initiative to virtualize network services traditionally run on proprietary, dedicated hardware.

  • network hub

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

  • network hypervisor

    A network hypervisor is a program that provides an abstraction layer for network hardware.  Network hypervisors allow network engineers to create virtual networks that are completely decoupled and independent from the underlying physical network.

  • 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 interface unit (NIU or Network Interface Device)

    A network interface unit (NIU) (sometimes called a network interface device) is a device that serves as a common interfacefor various other devices within a local area network (LAN), or as an interface to allow networked computers to connect to an outside 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 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 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 orchestration

    Network orchestration is a policy-driven approach to network automation that coordinates the hardware and software components a software application or service requires to run.

  • network packet

    A network packet is a small amount of data sent over Transmission Control Protocol/Internet Protocol (TCP/IP) networks.

  • 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

    In information technology, network security is the act of maintaining the integrity of a computer network and the data within it.

  • 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 a protocol used to synchronize computer clock times 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, sometimes referred to as data traffic, is the amount of data which 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.

  • O

    OA&M (operations, administration, and management)

    OA&M (operations, administration, and management) is a general term used to describe the costs, tasks involved, or other aspects of operating, administering, and managing something such as a computer network.

  • OF-Config (OpenFlow Configuration and Management Protocol)

    The OpenFlow Management and Configuration Protocol (OF-Config) is a protocol developed under the Open Networking Foundation used to manage physical and virtual switches in an OpenFlow environment.

  • 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.

  • 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.

  • OpenFlow controller

    An OpenFlow controller is an application that manages flow control in a software-defined networking (SDN) environment.

  • OpenFlow switch

    An OpenFlow switch is a software program or hardware device that forwards packets in a software-defined networking (SDN) environment.

  • OpenStack Neutron (formerly called Quantum)

    OpenStack Neutron is a cloud networking controller and a networking-as-a-service project within the OpenStack cloud computing initiative.

  • 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).

  • optical network (photonic network)

    An optical (photonic) network transmits information as optical rather than electronic signals: It uses light, not electrical currents, to convey data.

  • optoelectronics

    Optoelectronics is a branch of electronics that overlaps with physics.

  • 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)

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

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