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Bring yourself up to speed with our introductory content.

Get started

Bring yourself up to speed with our introductory content.

  • FCAPS (fault-management, configuration, accounting, performance, and security)

    FCAPS is a network management framework created by the International Organization for Standardization (ISO). FCAPS categorizes the working objectives of network management into five levels. The five levels are:  fault-management (F), the ... Continue Reading

  • connectionless

    In telecommunication, connectionless describes communication between two network end points in which a message can be sent from one end point to another without prior arrangement. Continue Reading

  • 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. Continue Reading

  • Intelligent Network (IN)

    Intelligent Network (IN) is a telephone network architecture originated by Bell Communications Research (Bellcore) in which the service logic for a call is located separately from the switching facilities, allowing services to be added or changed ... Continue Reading

  • DCE (Distributed Computing Environment)

    In network computing, DCE (Distributed Computing Environment) is an industry-standard software technology for setting up and managing computing and data exchange in a system of distributed computers. Continue Reading

  • duplex

    In telecommunication, duplex communication means that both ends of the communication can send and receive signals at the same time.Continue Reading

  • SDH (Synchronous Digital Hierarchy)

    SDH (Synchronous Digital Hierarchy) is a standard technology for synchronous data transmission on optical media.Continue Reading

  • connection-oriented

    In telecommunications, connection-oriented describes a means of transmitting data in which the devices at the end points use a preliminary protocol to establish an end-to-end connection before any data is sent.Continue Reading

  • run book

    In a computer system or network, a run book is a written set of procedures for the routine and exceptional operation of the system or network by an administrator or operator.Continue Reading

  • 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.Continue Reading

  • graceful degradation

    Graceful degradation is the ability of a computer, machine, electronic system or network to maintain limited functionality even when a large portion of it has been destroyed or rendered inoperative. The purpose of graceful degradation is to prevent ...Continue Reading

  • 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)Continue Reading

  • star network

    A star network is a local area network (LAN) in which all nodes (workstations or other devices) are directly connected to a common central computer.Continue Reading

  • Introduction -- Chapter 1 of 'Network Analysis, Architecture and Design'

    This chapter introduces the analysis, architecture, and design processes. Described are the fundamental concepts of the processes of network analysis, architecture, and design; systems and services; as well as their characteristics and prepares the ...Continue Reading

  • E-carrier system

    To see the relationship between the E-carrier system, the T-carrier system, and DS0 multiples, see digital signal X. E1 (or E- is a European digital transmission format devised by the ITU-TS and given the name by the Conference of European Postal ...Continue Reading

  • 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.Continue Reading

  • microwave

    The term microwave refers to electromagnetic energy having a frequency higher than 1 gigahertz (billions of cycles per second), corresponding to wavelength shorter than 30 centimeters.Continue Reading

  • in-band signaling

    In the public switched telephone network, (PSTN), in-band signaling is the exchange of signaling (call control) information on the same channel that the telephone call itself is using.Continue Reading

  • 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).Continue Reading

  • 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.Continue Reading

  • 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.Continue Reading

  • 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.Continue Reading

  • CCNA exam preparation guide

    A learning guide for CCNA exam preparation with book chapters, expert advice and quiz.Continue Reading

  • predictive dialer

    A predictive dialer is a telephone control system that automatically calls a list of telephone numbers in sequence, screening out no-answers, busy signals, answering machines and disconnected numbers while predicting at what point a human caller ...Continue Reading

  • spread spectrum

    Spread spectrum is a form of wireless communications in which the frequency of the transmitted signal is deliberately varied.Continue Reading

  • 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.Continue Reading

  • PCS (personal communications service)

    PCS (personal communications service) is a wireless phone service similar to cellular telephone service but emphasizing personal service and extended mobility. (Continued...)Continue Reading

  • permanent virtual circuit (PVC)

    A permanent virtual circuit (PVC) is a software-defined logical connection in a network such as a frame relay network.Continue Reading

  • Network+ certification: Where does CompTIA Network+ take you? Part 3

    Network+ certification: Where does CompTIA Network+ take you?Continue Reading

  • 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.Continue Reading

  • network analyzer (protocol analyzer or packet analyzer)

    A network analyzer is a combination of hardware and programming, or in some cases a stand-alone hardware device, that can be installed in a computer or network to enhance protection against malicious activity... (Continued)Continue Reading

  • collision

    In a half duplex Ethernet network, a collision is the result of two devices on the same network attempting to transmit data at exactly the same time.Continue Reading

  • wire speed

    Wire speed refers to the rate of data transfer a given telecommunication technology provides at the physical wire level.Continue Reading

  • 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).Continue Reading

  • weighted fair queueing (WFQ)

    Weighted fair queueing (WFQ) is a method of automatically smoothing out the flow of data in packet-switched communication networks by sorting packets to minimize the average latency and prevent exaggerated discrepancies between the transmission ...Continue Reading

  • 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.Continue Reading

  • network operations center (NOC)

    A network operations center (NOC) is a place from which administrators supervise, monitor and maintain a telecommunications network.Continue Reading

  • network access server (NAS)

    A network access server (NAS) is a computer server that enables an independent service provider (ISP) to provide connected customers with Internet access.Continue Reading

  • 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.Continue Reading

  • virtual network computing (VNC)

    Virtual network computing (VNC) is a type of remote-control software that makes it possible to control another computer over a network connection...Continue Reading

  • terminal emulation

    Terminal emulation is the ability to make one computer terminal, typically a PC, appear to look like another, usually older type of terminal so that a user can access programs originally written to communicate with the other terminal type.Continue Reading

  • Open source network tools

    Some of the most commonly used, enterprise-ready open source tools are used for networking applications; likewise, many networking tasks can be accomplished quickly and cheaply using open source tools. In this guide, we present advice and resources ...Continue Reading

  • 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)Continue Reading

  • VPN appliance

    A VPN (virtual private network) appliance is a network device equipped with enhanced security features... (Continued)Continue Reading

  • fax

    A fax (short for facsimile and sometimes called telecopying) is the telephonic transmission of scanned-in printed material (text or images), usually to a telephone number associated with a printer or other output device.Continue Reading

  • Routing versus routed protocols and the CCNA

    Many networking professionals don't really know what a routing protocol is or does. There are those who also couldn't tell you the difference between a routing protocol and a routed protocol. If you are working as a network engineer or preparing to ...Continue Reading

  • OpenNMS, an introduction: Affordable network management

    Open source expert Maria Winslow brings network managers up to speed about the free open source enterprise-grade network-management system OpenNMS.Continue Reading

  • Wireless networking (CWNA)

    Do you think you know a lot about wireless networking? Are you interested in taking the Certified Wireless Network Administrator (CWNA) exam? Test your knowledge with our 13-question quiz on wireless networking!Continue Reading

  • Content Delivery Networking: an introduction

    Doug Downer gives an overview of Content Delivery Network (CDN) technology and its components, which bring together the functionality of file access, caching, multimedia delivery and application processing.Continue Reading

  • multicast

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

  • Securing your Layer 2 network: Don't overlook the basics

    Before dropping substantial cash on a fancy surveillance system, most sensible home owners would ensure that their doors and windows were locked. Similarly, there are simple security measures you can take to configure your systems for Layer 2 ...Continue Reading

  • home server

    A home server is a computer that functions as a server in a client-server home network.Continue Reading

  • 802.11 Learning Guide

    802.11 is perhaps the fastest-changing network protocol around. We've gathered a wealth of information to get you up-to-speed quickly on the various specifications. Learn about all the 802.11 wireless LAN (WLAN) specifications in this learning guide.Continue Reading

  • Wireless LAN quiz answers

    Wireless LANs quiz answer key.Continue Reading

  • Wireless LAN quiz

    Take our wireless LAN quiz to find out how much you know about WLAN technologies.Continue Reading

  • E.164

    E.164 is an international numbering plan for public telephone systems in which each assigned number contains a country code (CC), a national destination code (NDC), and a subscriber number (SN).Continue Reading

  • 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").Continue Reading

  • subcarrier

    A subcarrier is one telecommunication signal carrier that is carried on top of another carrier so that effectively two signals are carried at the same time.Continue Reading

  • 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.Continue Reading

  • Serial Digital Interface (SDI)

    Serial Digital Interface (SDI) is a standard for digital video transmission over coaxial cable.Continue Reading

  • keystone jack

    A keystone jack is a female connector used in data communications, particularly local area networks (LANs).Continue Reading

  • network perimeter

    A network perimeter is the boundary between the private and locally managed-and-owned side of a network and the public and usually provider-managed side of a network.Continue Reading

  • discrete multitone (DMT)

    Discrete multitone (DMT) is a method of separating a Digital Subscriber Line (DSL) signal so that the usable frequency range is separated into 256 frequency bands (or channels) of 4.3125 KHz each.Continue Reading

  • triangulation

    Triangulation is a process by which the location of a radio transmitter can be determined by measuring either the radial distance, or the direction, of the received signal from two or three different points.Continue Reading

  • long-haul optics

    Long-haul optics refers to the transmission of visible light signals over optical fiber cable for great distances, especially without or with minimal use of repeaters.Continue Reading

  • coarse wavelength division multiplexing (CWDM)

    Coarse wavelength division multiplexing (CWDM) is a method of combining multiple signals on laser beams at various wavelengths for transmission along fiber optic cables, such that the number of channels is fewer than in dense wavelength division ...Continue Reading

  • gigapop (gigabit point-of-presence)

    Gigapop is short for gigabit point-of-presence, an access point to Internet2, the network collaboration between universities and partners in industry and government to develop advanced Internet technologies and applications such as telemedicine and ...Continue Reading

  • HELLO packet

    In the Open Shortest Path First (OSPF) communications protocol - which enables network routers to share information with each other, a HELLO packet is a special packet (message) that is sent out periodically from a router to establish and confirm ...Continue Reading

  • hoot-n-holler

    In telecommunications, a hoot-n-holler is a dedicated "always on" connection used for two-way business-to-business voice communication.Continue Reading

  • Home Location Register (HLR)

    The Home Location Register (HLR) is the main database of permanent subscriber information for a mobile network.Continue Reading

  • IPLC (international private leased circuit)

    An IPLC (international private leased circuit) is a point-to-point private line used by an organization to communicate between offices that are geographically dispersed throughout the world.Continue Reading

  • GNSS (Global Navigation Satellite System)

    GNSS (Global Navigation Satellite System) is a satellite system that is used to pinpoint the geographic location of a user's receiver anywhere in the world.Continue Reading

  • Simputer (simple inexpensive mobile computer)

    The Simputer (short for simple inexpensive mobile computer) is an inexpensive, Web-enabled handheld computer designed for use by people in developing countries.Continue Reading

  • wrap plug

    A wrap plug, also known as a loopback plug, is a special plug that can be inserted into a port on a communications device to perform a diagnostic test called a loopback test.Continue Reading

  • electronic program guide (EPG)

    An electronic program guide (EPG) is an application used with digital set-top boxes and newer television sets to list current and scheduled programs that are or will be available on each channel and a short summary or commentary for each program.Continue Reading

  • satellite news gathering (SNG)

    Satellite news gathering (SNG) is the use of mobile communications equipment for the purpose of worldwide newscasting.Continue Reading

  • 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.Continue Reading

  • tree network

    In telecommunication networks, a tree network is a combination of two or more star networks connected together.Continue Reading

  • file server

    In the client/server model, a file server is a computer responsible for the central storage and management of data files so that other computers on the same network can access the files.Continue Reading

  • 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.Continue Reading

  • QAM (quadrature amplitude modulation)

    QAM (quadrature amplitude modulation) is a method of combining two amplitude-modulated (AM) signals into a single channel, thereby doubling the effective bandwidth.Continue Reading

  • Cisco Certified Network Professional (CCNP)

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

  • reverse Telnet (direct Telnet)

    Reverse Telnet (sometimes called direct Telnet) is the initiation of a Telnet session from a computer system to one of its remote users.Continue Reading

  • 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).Continue Reading

  • 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.Continue Reading

  • data link control (DLC)

    DLC also is an abbreviation for digital loop carrier.Continue Reading

  • connection

    In telecommunication and computing in general, a connection is the successful completion of necessary arrangements so that two or more parties (for example, people or programs) can communicate at a long distance.Continue Reading

  • Personal Access Communications System (PACS)

    Personal Access Communications System (PACS) is a type of wireless telephone network compatible with telephone sets, answering machines, fax machines, and computers.Continue Reading

  • Evernet

    The term Evernet has been used to describe the convergence of wireless, broadband, and Internet telephony technologies that will result in the ability to be continuously connected to the Web anywhere using virtually any information device.Continue Reading

  • satellite Internet connection

    A satellite Internet connection is an arrangement in which the upstream (outgoing) and the downstream (incoming) data are sent from, and arrive at, a computer through a satellite.Continue Reading

  • 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.Continue Reading

  • fast retransmit and recovery (FRR)

    In TCP/IP, fast retransmit and recovery (FRR) is a congestion control algorithm that makes it possible to quickly recover lost data packets.Continue Reading

  • 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.Continue Reading

  • registered port numbers

    The registered port numbers are the port numbers that companies and other users register with the Internet Corporation for Assigned Names and Numbers (ICANN) for use by the applications that communicate using the Internet's Transmission Control ...Continue Reading

  • 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.Continue Reading

  • spatial division multiple access (SDMA)

    Also see frequency division multiple access (FDMA) and time division multiple access (TDMA).Continue Reading

  • visitor-based networking (VBN)

    Visitor-based networking (VBN) is the provision of high-speed Internet access for mobile PC users in need of temporary service in public places.Continue Reading

  • 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 ...Continue Reading

  • 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).Continue Reading

  • telephone jacks

    In the U. S., telephone jacks are also known as registered jacks, sometimes described as RJ-XX, and are a series of telephone connection interfaces (receptacle and plug) that are registered with the U.S. Federal Communications Commission (FCC).Continue Reading

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