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.

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    10 Gigabit Ethernet (10 GbE)

    10 Gigabit Ethernet (10 GbE) is a telecommunication technology that offers data speeds up to 10 billion bits per second.

  • 100 Gigabit Ethernet (100GbE)

    100 Gigabit Ethernet (100GbE) is a standard in development that will enable the transfer of Ethernet frames at 100 gigabits per second (gp/s). The 100GbE standard is for core switching. A 40GbE standard, in development simultaneously, is designed for server connectivity. Both standards are expected to be ratified in 2010.

  • 1000BASE-T

    1000BASE-T is Gigabit Ethernet (1 gigabit is 1000 megabits per second) on copper cables, using four pairs of Category 5 unshielded twisted pair to achieve the gigabit data rate.

  • 100BASE-T

    In 100 Mbps (megabits per second) Ethernet (known as Fast Ethernet), there are three types of physical wiring that can carry signals: 100BASE-T4 (four pairs of telephone twisted pair wire) 100BASE-TX (two pairs of data grade twisted-pair wire) 100BASE-FX (a two-strand optical fiber cable) This designation is an Institute of Electrical and Electronics Engineers shorthand identifier.

  • 10BASE-36

    10BASE-36 is a type of physical cabling defined in the IEEE 802.3 (Ethernet) standard for broadband application.

  • 10BASE-T

    10BASE-T, one of several physical media specified in the IEEE 802.3 standard for Ethernet local area networks (LANs), is ordinary telephone twisted pair wire.

  • 32-bit IP addressing

    32-bit IP addressing is the IP address scheme used in Internet Protocol 4 (IPv6 uses a 128-bit system)... (Continued)

  • 3G (third generation of mobile telephony)

    3G refers to the third generation of cellular technology that enables mobile telephony.

  • 3GPP (3rd Generation Partnership Project)

    The 3rd Generation Partnership Project (3GPP) is a collaborative project between a group of telecommunications associations with the initial goal of developing globally applicable specifications for third-generation (3G) mobile systems.

  • 6G

    6G (sixth-generation wireless) is the successor to 5G cellular technology -- 6G networks will be able to use higher frequencies than 5G networks and provide substantially higher capacity and much lower latency.

  • streaming network telemetry

    Streaming network telemetry is a real-time data collection service in which network devices such as routers, switches and firewalls continuously push network health data and interface measurements to a centralized collector.

  • What is 5G?

    Fifth-generation wireless (5G) is the latest iteration of cellular technology. Unlike 4G, which requires large, high-power cell towers to radiate signals over longer distances, 5G wireless signals are transmitted through large numbers of small cell stations located on places like light poles or building roofs.

  • A

    AAUI (Apple attachment unit interface)

    An AAUI (Apple attachment unit interface) is the 14- or 15-pin port or connection interface on earlier models of Macintosh computers that allowed it to be connected by a short interface cable (or "transceiver") to an Ethernet cable.

  • ACK

    In some digital communication protocols, ACK is the name of a signal that data has been received successfully (for example, with an acceptable number of errors).

  • adaptive routing (dynamic routing)

    Adaptive routing, also called dynamic routing, is a process for determining the optimal path a data packet should follow through a network to arrive at a specific destination. Adaptive routing can be compared to a commuter taking a different route to work after learning that traffic on his usual route is backed up.

  • address

    An address can mean the unique location of either ( an Internet server, (2) a specific file (for example, a Web page), or (3) an e-mail user. It is also used to specify the location of data within computer storage.

  • Address Resolution Protocol (ARP)

    Address Resolution Protocol (ARP) is a procedure for mapping a dynamic Internet Protocol address (IP address) to a permanent physical machine address in a local area network (LAN).

  • ADSL (Asymmetric Digital Subscriber Line)

    Also see Fast Guide to DSL. ADSL (Asymmetric Digital Subscriber Line) is a technology for transmitting digital information at a high bandwidth on existing phone lines to homes and businesses.

  • aggregator

    Like its synonym concentrator, an aggregator is any device that serves multiple other devices or users either with its own capabilities or by forwarding transmissions in a more concentrated and economical way.

  • akamaize

    For a Web site, to akamaize (pronounced AHK-uh-myez) is to accelerate the delivery of Web files by placing copies on servers closer to the user than the server that delivers the main file for a Web page.

  • Aloha (Aloha method)

    Aloha, also called the Aloha method, refers toa simple communications scheme in which each source (transmitter) in a network sends data wheneverthere is a frame to send.

  • American Wire Gauge (AWG)

    American Wire Gauge (AWG) is a U.S. standard set of non-ferrous wire conductor sizes.

  • anti-replay protocol

    The anti-replay protocol is part of the Internet Engineering Task Force (IETF) Internet Protocol Security (IPSec) standard.

  • anycast

    In Internet Protocol Version 6 (IPv6), anycast is communication between a single sender and the nearest of several receivers in a group. The term exists in contradistinction to multicast, communication between a single sender and multiple receivers, and unicast, communication between a single sender and a single receiver in a network.

  • AppleTalk

    AppleTalk is a set of local area network communication protocols originally created for Apple computers.

  • application delivery controller (ADC)

    An application delivery controller (ADC) is a network component that manages and optimizes how client machines connect to web and enterprise application servers.

  • Application layer

    Sitting at Layer 7 -- the very top of the Open Systems Interconnection (OSI) communications model -- the application layer provides services for an application program to ensure that effective communication with another application program on a network is possible.

  • application-aware networking (app-ware networking)

    Application-aware networking is the capacity of an intelligent network to maintain current information about applications that connect to it and, as a result, optimize their functioning as well as that of other applications or systems that they control.

  • application-defined networking

    Application-defined networking (ADN) is a networking scenario in which applications have the ability to adapt network environments to meet their needs, rather than having resources allocated by the network.

  • ARCNET

    ARCNET is a widely-installed local area network (LAN) technology that uses a token-bus scheme for managing line sharing among the workstations and other devices connected on the LAN.

  • Arista Extensible Operating System (Arista EOS)

    Extensible Operating System (EOS) is a scalable network operating system (OS) that offers high availability, streamlines maintenance processes, and enhances network security.

  • ARPANET

    ARPANET was the network that became the basis for the Internet. Based on a concept first published in 1967, ARPANET was developed under the direction of the U.S. Advanced Research Projects Agency (ARPA). In 1969, the idea became a modest reality with the interconnection of four university computers.

  • asymmetric communications

    In telecommunications, the term asymmetric (also asymmetrical or non-symmetrical) refers to any system in which the data speed or quantity differs in one direction as compared with the other direction, averaged over time.

  • Asynchronous

    In general, asynchronous -- pronounced ay-SIHN-kro-nuhs, from Greek asyn-, meaning "not with," and chronos, meaning "time" -- is an adjective describing objects or events that are not coordinated in time.

  • attenuation

    Attenuation is a general term that refers to any reduction in the strength of a signal.

  • autonomous system (AS)

    On the Internet, an autonomous system (AS) is the unit of router policy, either a single network or a group of networks that is controlled by a common network administrator (or group of administrators) on behalf of a single administrative entity (such as a university, a business enterprise, or a business division).

  • autotrunking

    Autotrunking is a function that can be activated for one or more switch ports in a Cisco system of virtual local area networks (VLANs), making those ports capable of carrying traffic for any or all of the VLANs accessible by a particular switch....

  • average revenue per user or average revenue per unit (ARPU)

    Average revenue per user or average revenue per unit (ARPU) is an expression of the income generated by a typical subscriber or device per unit time in a telecommunications network... (Continued)

  • network availability

    Network availability is the amount of uptime in a network system over a specific time interval.

  • B

    B-channel (bearer channel)

    In the Integrated Services Digital Network (ISDN), the B-channel is the channel that carries the main data.

  • backbone

    A backbone is a larger transmission line that carries data gathered from smaller lines that interconnect with it.

  • balun

    A balun is a device that joins a balanced line (one that has two conductors, with equal currents in opposite directions, such as a twisted pair cable) to an unbalanced line (one that has just one conductor and a ground, such as a coaxial cable).

  • band

    In telecommunication, a band - sometimes called a frequency band - is a specific range of frequencies in the radio frequency (RF) spectrum, which is divided among ranges from very low frequencies (vlf) to extremely high frequencies (ehf).

  • bandwidth (network bandwidth)

    Network bandwidth is a measurement indicating the maximum capacity of a wired or wireless communications link to transmit data over a network connection in a given amount of time.

  • baseband

    Describes a telecommunication system in which information is carried in digital form on a single unmultiplexed signal channel on the transmission medium.

  • baseboard management controller (BMC)

    A baseboard management controller (BMC) is a specialized service processor that monitors the physical state of a computer, network server or other hardware device using sensors and communicating with the system administrator through an independent connection... (continued)

  • baud

    Baud was the prevalent measure for data transmission speed until replaced by a more accurate term, bps (bits per second).

  • beamforming

    Beamforming is a type of RF (radio frequency) management in which an access point uses multiple antennas to send out the same signal.

  • BGAN (Broadband Global Area Network)

    BGAN (Broadband Global Area Network) is a mobile communications system created to transmit broadband wireless voice and data communications almost anywhere on the earth's surface.

  • BGP (Border Gateway Protocol)

    BGP (Border Gateway Protocol) is the protocol underlying the global routing system of the internet.

  • Big Switch Big Network Controller

    Big Network Controller is the SDN controller for the Open Software Defined Network (SDN), a product suite for network virtualization released in November of 2012 by Big Switch Networks.

  • Big Switch Networks

    Big Switch Networks is a network virtualization and SDN (software-defined networking) company that was founded in 2010.

  • Big Switch Networks Big Tap

    Big Tap is a network monitoring application that runs on Big Network Controller, the SDN controller for the Open Software-Defined Network (SDN).

  • Big Switch Networks Big Virtual Switch

    Big Virtual Switch is a data center network virtualization application that runs on Big Network Controller, the SDN controller for the Open Software-Defined Network (SDN).

  • big-endian and little-endian

    Endianness is a term that describes the order in which a sequence of bytes are stored in computer memory. Endianness can be either big or small, with the adjectives referring to which value is stored first.

  • bit stuffing

    Bit stuffing is the insertion of one or more bits into a transmission unit as a way to provide signaling information to a receiver... (Continued)

  • bits per second (bps or bit/sec)

    In data communications, bits per second (bps or bit/sec) is a common measure of data speed for computer modems and transmission carriers.

  • BNC (Bayonet Neil-Concelman or British Naval Connector)

    A BNC (Bayonet Neil-Concelman, or sometimes British Naval Connector) connector is used to connect a computer to a coaxial cable in a 10BASE-2 Ethernet network. 10BASE-2 is a 10 MHz baseband network on a cable extending up to 185 meters - the 2 is a rounding up to 200 meters - without a repeater cable.

  • bogon

    A bogon is an illegitimate IP address that falls into a set of IP addresses that have not been officially assigned to an entity by an internet registration institute, such as the Internet Assigned Number Authority (IANA).

  • BOOTP (Bootstrap Protocol)

    BOOTP (Bootstrap Protocol) is a protocol that lets a network user be automatically configured (receive an IP address) and have an operating system booted (initiated) without user involvement.

  • bottleneck

    A bottleneck is a stage in a process that causes the entire process to slow down or stop. In a communications context, a bottleneck is a point in the enterprise where the flow of data is impaired or stopped entirely... (Continued)

  • branch office box (BOB)

    A Branch Office Box (BOB) is a server appliance that has been optimized to provide distributed support for simple utility functions that are required locally but are difficult to provide over a WAN... (Continued)

  • broadband

    In general, broadband refers to telecommunication in which a wide band of frequencies is available to transmit information.

  • broadband voice gateway

    A broadband voice gateway is a device that allows you to make telephone calls over a high-speed Internet connection rather than through a regular telephone outlet without having to go through your computer.

  • brouter

    A brouter (pronounced BRAU-tuhr or sometimes BEE-rau-tuhr) is a network bridge and a router combined in a single product.

  • burst

    Burst is a term used in a number of information technology contexts to mean a specific amount of data sent or received in one intermittent operation.

  • bus network

    A bus network is an arrangement in a local area network (LAN) in which each node (workstation or other device) is connected to a main cable or link called the bus.

  • C

    cable head-end

    A cable head-end (or headend) is the facility at a local cable TV office that originates and communicates cable TV services and cable modem services to subscribers.

  • cable modem termination system (CMTS)

    A cable modem termination system (CMTS) is a component that exchanges digital signals with cable modems on a cable network.

  • cable TV or CATV (community antenna television)

    Cable TV is also known as "CATV" (community antenna television).

  • campus network

    A campus network is a proprietary local area network (LAN) or set of interconnected LANs serving a corporation, government agency, university, or similar organization.

  • CAPWAP (Control and Provisioning of Wireless Access Points)

    CAPWAP (Control and Provisioning of Wireless Access Points) is a standardized protocol that enables wireless LAN (WLAN) controllers to centrally manage a group of wireless access points (APs).

  • care-of address

    In Internet routing, a care-of address is a temporary IP address for a mobile node (mobile device) that enables message delivery when the device is connecting from somewhere other than its home network.

  • carrier cloud

    A carrier cloud is a cloud computing system, or network of servers that store data in a way that it is easily accessible from multiple locations, that is owned and operated by a traditional telecommunications service provider.

  • carrier detect

    Carrier detect (see modem lights) is a control signal between a modem and a computer that indicates that the modem detects a "live" carrier that can be used for sending and receiving information.

  • Carrier Ethernet

    Carrier Ethernet is the use of high-bandwidth Ethernet technology for Internet access and for communication among business, academic and government local area networks (LANs)... (Continued)

  • carrier signal

    A carrier signal is a transmitted electromagnetic pulse or wave at a steady base frequency of alternation on which information can be imposed by increasing signal strength, varying the base frequency, varying the wave phase, or other means... (Continued)

  • carrier-to-noise ratio (CNR or C/N)

    In communications, the carrier-to-noise ratio, often written CNR or C/N, is a measure of the received carrier strength relative to the strength of the received noise.

  • CATV (community access television)

    CATV (originally "community antenna television," now often "community access television") is more commonly known as "cable TV." In addition to bringing television programs to those millions of people throughout the world who are connected to a community antenna, cable TV is an increasingly popular way to interact with the World Wide Web and other new forms of multimedia information and entertainment services.

  • CCITT or ITU-T (Telecommunication Standardization Sector of the International Telecommunications)

    The CCITT, now known as the ITU-T (for Telecommunication Standardization Sector of the International Telecommunications Union), is the primary international body for fostering cooperative standards for telecommunications equipment and systems.

  • CCNA certification

    Cisco Certified Network Associate (CCNA) is a technical certification that Cisco offers for early-career networking professionals.

  • CDMA (Code-Division Multiple Access)

    CDMA (Code-Division Multiple Access) refers to any of several protocols used in second-generation (2G) and third-generation (3G) wireless communications.

  • CDN (content delivery network)

    A CDN (content delivery network), also called a content distribution network, is a group of geographically distributed and interconnected servers that provide cached internet content from a network location closest to a user to accelerate its delivery.

  • CenturyLink

    CenturyLink is an integrated telecommunications company that provides a wide variety of products and services to clients across the globe, including networking, cloud service and security solutions.

  • Certified Wireless Networking Professional (CWNP)

    Certified Wireless Networking Professional (CWNP)is the name for the family of wireless certifications from Planet3Wireless.

  • chatty protocol

    A chatty protocol is an application or routing protocol that requires a client or server to wait for an acknowledgement before it can transmit again.

  • CIDR (Classless Inter-Domain Routing or supernetting)

    CIDR (Classless Inter-Domain Routing) -- also known as supernetting -- is a method of assigning Internet Protocol (IP) addresses that improves the efficiency of address distribution and replaces the previous system based on class A, class B and class C networks.

  • circuit-switched

    Circuit-switched is a type of network in which a physical path is obtained for and dedicated to a single connection between two end-points in the network for the duration of the connection.

  • Cisco Certified Entry Networking Technician (CCENT)

    Cisco Certified Entry Networking Technician (CCENT) is a now-retired certification offered by Cisco, as part of their certification program.

  • Cisco Certified Internetwork Expert (CCIE certification)

    Cisco Certified Internetwork Expert (CCIE certification) is a series of technical certifications for senior networking professionals who design, build, implement, maintain and troubleshoot complex enterprise networking infrastructures.

  • Cisco Certified Network Professional (CCNP)

    Cisco Certified Network Professional (CCNP) is an intermediate-level certification in the Cisco certified professional program.

  • Cisco Enterprise Agreement (EA)

    Cisco Enterprise Agreement (EA) is a software buying program that digitizes and simplifies license management for Cisco suite customers.

  • Cisco Information Security Specialist (CISS)

    Cisco Information Security Specialist (CISS) is an entry-level certification attesting that the holder has demonstrated the foundational knowledge and skills required to install and support a Cisco Self-Defending Network... (Continued)

  • Cisco Integrated Service Routers Generation 2 (ISR G2)

    ISR G2 is a second generation Integrated Services Router (ISR) from Cisco Systems, Inc.

  • Cisco IOS (Cisco Internetwork Operating System)

    Cisco IOS (Internetwork Operating System) is a proprietary operating system that runs on Cisco Systems routers and switches.

  • Cisco LISP (Location Identifier Separation Protocol)

    LISP (Location Identifier Separation Protocol) is a routing and addressing architecture developed by Cisco Systems. LISP creates two addresses for each network node: one for its identity and another for its location in the network.

  • Cisco Performance Routing (PfR)

    Cisco Performance Routing (PfR) is a way of sending network packets based on intelligent path control.

  • Class of Service (CoS)

    Class of Service (CoS) is a way of managing traffic in a network by grouping similar types of traffic (for example, e-mail, streaming video, voice, large document file transfer) together and treating each type as a class with its own level of service priority.

  • client-server model (client-server architecture)

    Client-server is a relationship in which one program (the client) requests a service or resource from another program (the server).

  • clone

    A clone is an identical copy of something and is a term that first became familiar to the public from the biosciences.

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