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• 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 ... Continue Reading

• How do I...choose a VPN for my small business?

  A virtual private network (VPN)is a way to use a public telecommunication infrastructure, such as the Internet,to provide remote offices or individual users with secure access to their organization's network. Continue Reading

• frequency-shift keying (FSK)

  Frequency-shift keying (FSK) is a method of transmitting digital signals. Continue Reading

• cyclic redundancy checking

  Cyclic redundancy checking is a method of checking for errors in data that has been transmitted on a communications link. Continue Reading

• 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. Continue Reading

• Definitions to Get Started

  • SYN scanning
  • network packet
  • Stream Control Transmission Protocol (SCTP)
  • port

  • passive optical network (PON)
  • megabits per second (Mbps)
  • FDDI (Fiber Distributed Data Interface)
  • American Wire Gauge (AWG)

  View All Definitions

• 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.Continue Reading

• 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.Continue Reading

• stateful inspection

  Stateful inspection is a firewall technology that monitors the state of active connections and uses this information to determine which network packets to allow through the firewall. Stateful inspection is also known as dynamic packet filtering.Continue Reading

• green networking

  Green networking is the practice of selecting energy-efficient networking technologies and products, and minimizing resource use whenever possible.Continue Reading

• beamforming

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

• 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.Continue Reading

• Seebeck effect

  The Seebeck effect describes the generation of electricity following the connection of two dissimilar electrical conductors or semiconductors that illustrates the thermoelectric effect. Continue Reading

• 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 ...Continue Reading

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

  MDI/MDIX is a type of Ethernet port connection using twisted pair cabling.Continue Reading

• CSU/DSU (Channel Service Unit/Data Service Unit)

  A CSU/DSU (Channel Service Unit/Data Service Unit) is a hardware device about the size of an external modem that converts a digital data frame from the communications technology used on a local area network (LAN) into a frame appropriate to a ...Continue Reading

• CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance)

  CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) is a protocol for carrier transmission in 802.11 networks.Continue Reading

• 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 ...Continue Reading

• route summarization (route aggregation)

  Route summarization, also called route aggregation, is a method of minimizing the number of routing tables in an IP (Internet Protocol) network. It works by consolidating selected multiple routes into a single route advertisement, in contrast to ...Continue Reading

• Internet metering

  Internet metering is a service model in which an Internet service provider (ISP) tracks the customer's use of bandwidth and charges accordingly. Typically, the customer selects a service package with a flat rate up to a specified limit and pays,...Continue Reading

• 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.Continue Reading

• Learning Path: Telephony and Wide Area Networks

  TELEPHONY AND WIDE AREA NETWORKS...circuit - PSTN - Plain Old Telephone Service (POTS) - telephone jacks - dial-up - acoustic coupler - modem - 56flex - 56 Kbps (x2) - handshaking - V.xx standards - local loop - central office - LIDB - dedicated ...Continue Reading

• Ethernet Glossary

  After you've finished, you can test your knowledge with Quiz #28: Ethernet.Continue Reading

• NIS (Network Information System)

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

• IDSL

  IDSL is a system in which digital data is transmitted at 128 Kbps on a regular copper telephone line (twisted pair) from a user to a destination using digital (rather than analog or voice) transmission, bypassing the telephone company's central ...Continue Reading

• IT Survival Kit: Networking refreshers

  Quick Network Security & Hardware Refreshers School is out for college students across the US, but the learning never stops for IT professionals.Continue Reading

• Optical Carrier levels (OCx)

  The Synchronous Optical Network (SONET) includes a set of signal rate multiples for transmitting digital signals on optical fiber.Continue Reading

• flow routing

  Flow routing is a network routing technology that takes variations in the flow of data into account to increase routing efficiency... (Continued)Continue Reading

• 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)Continue Reading

• 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.Continue Reading

• DSLAM (Digital Subscriber Line Access Multiplexer)

  A DSLAM (Digital Subscriber Line Access Multiplexer) is a network device, usually at a telephone company central office, that receives signals from multiple customer Digital Subscriber Line (DSL) connections and puts the signals on a high-speed ...Continue Reading

• 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.Continue Reading

• backbone

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

• T-carrier system

  To see the relationship between T-carrier, E-carrier, and DS0 multiples, see digital signal X. The T-carrier system, introduced by the Bell System in the U.S. in the 1960s, was the first successful system that supported digitized voice transmission.Continue Reading

• 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)Continue Reading

• erlang

  The Erlang programming language is not the same thing as the erlang, a unit of traffic density.Continue Reading

• fiber jumper

  A fiber jumper, sometimes called a fiber patch cord is a length of fiber cabling fitted with LC, SC, MTRJ or ST connectors at each end... (Continued)Continue Reading

• 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....Continue Reading

• GVRP (GARP VLAN Registration Protocol or Generic VLAN Registration Protocol)

  GVRP (GARP VLAN Registration Protocol or Generic VLAN Registration Protocol) is a protocol that facilitates control of virtual local area networks (VLANs) within a larger network . GVRP conforms to the IEEE 802.1Q specification, which defines a ...Continue Reading

• tunneling or port forwarding

  Tunneling is the transmission of data intended for use only within a private, usually corporate network through a public network in such a way that the routing nodes in the public network are unaware that the transmission is part of a private ...Continue Reading

• 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.Continue Reading

• fixed-length subnet mask (FLSM)

  A fixed-length subnet mask (FLSM) is a sequence of numbers of unchanging length that streamlines packet routing within the subnets of a proprietary network... (Continued)Continue Reading

• 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 ...Continue Reading

• packet loss

  Packet loss is the failure of one or more transmitted packets to arrive at their destination... (Continued)Continue Reading

• delay-tolerant network

  A delay-tolerant network is a network designed to operate effectively over extreme distances such as those encountered in space communications or on an interplanetary scale... (Continued)Continue Reading

• logical router

  A logical router is a configured partition of a traditional network hardware, or "physical," router.Continue Reading

• Certified Wireless Networking Professional (CWNP)

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

• infrared transmission

  Infrared transmission refers to energy in the region of the electromagnetic radiation spectrum at wavelength s longer than those of visible light, but shorter than those of radioContinue Reading

• GTAG (Global Tag)

  GTAG (Global Tag) is a standardization initiative of the Uniform Code Council (UCC) and the European Article Numbering Association (EAN) for asset tracking and logistics based on radio frequency identification (RFID).Continue Reading

• virtual area network (VAN)

  A virtual area network (VAN) is a network on which users are enabled to share a more visual sense of community through high band-width connections.Continue Reading

• virtual private LAN service (VPLS)

  Virtual private LAN service (VPLS) is a technology that makes it possible to connect geographically dispersed local area networks (LANs) logically over the Internet.Continue Reading

• GMPLS (Generalized Multiprotocol Label Switching or Multiprotocol Lambda Switching)

  GMPLS (Generalized Multiprotocol Label Switching), also known as Multiprotocol Lambda Switching, is a technology that provides enhancements to Multiprotocol Label Switching (MPLS) to support network switching for time, wavelength, and space ...Continue Reading

• Layer Two Tunneling Protocol (L2TP)

  Layer Two Tunneling Protocol (L2TP) is an extension of the Point-to-Point Tunneling Protocol (PPTP) used by an Internet service provider (ISP) to enable the operation of a virtual private network (VPN) over the Internet.Continue Reading

• routing table

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

• hardware load-balancing device (HLD)

  A hardware load-balancing device (HLD), also known as a layer 4-7 router, is a physical unit that directs computers to individual servers in a network, based on factors such as server processor utilization, the number of connections to a server, or ...Continue Reading

• split horizon

  Split horizon is a method of preventing a routing loop in a network.Continue Reading

• start of authority record

  A start of authority (SOA) record is information stored in a domain name system (DNS) zone about that zone and about other DNS records.Continue Reading

• core router

  A core router is a router that forwards packets to computer hosts within a network (but not between networks).Continue Reading

• home agent

  In Mobile Internet Protocol (Mobile IP), a home agent is a router on a mobile node's home network that maintains information about the device's current location, as identified in its care-of address.Continue Reading

• cross-bar switch

  In a network, a cross-bar switch is a device that is capable of channeling data between any two devices that are attached to it up to its maximum number of ports.Continue Reading

• mrouter (multicast router)

  An mrouter, or multicast router, is a router program that distinguishes between multicast and unicast packets and determines how they should be distributed along the Multicast Internet (sometimes known as the Multicast Backbone or MBone).Continue Reading

• one-armed router

  A one-armed router is a router that routes traffic between virtual local area networks (VLANs).Continue Reading

• dynamic port numbers (private port numbers)

  The dynamic port numbers (also known as the private port numbers) are the port numbers that are available for use by any application to use in communicating with any other application, using the Internet's Transmission Control Protocol (TCP) or the ...Continue Reading

• 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 (...Continue Reading

• Real-Time Transport Protocol (RTP)

  The Real-Time Transport Protocol (RTP) is an Internet protocol standard that specifies a way for programs to manage the real-time transmission of multimedia data over either unicast or multicast network services.Continue Reading

• encapsulation

  In general, encapsulation is the inclusion of one thing within another thing so that the included thing is not apparent.Continue Reading

• 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.Continue Reading

• 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.Continue Reading

• Link Control Protocol (LCP)

  In the Point-to-Point Protocol (PPP), the Link ControlProtocol (LCP) establishes, configures, and tests data-link Internet connections.Continue Reading

• FG-D (Feature Group D)

  FG-D (Feature Group D) is a type of telecommunication trunk used to provide "equal access" capability from telecommunication carriers and central offices (where the switching equipment is located and customer lines are connected and terminated) to ...Continue Reading

• Gigabit Ethernet

  Gigabit Ethernet, a transmission technology based on the Ethernet frame format and protocol used in local area networks (LANs), provides a data rate of 1 billion bits per second (one gigabit). (Continued...)Continue Reading

• COFDM

  COFDM is a modulation scheme that divides a single digital signal across 1,000 or more signal carriers simultaneously.Continue Reading

• EIGRP (Enhanced Interior Gateway Routing Protocol)

  EIGRP (Enhanced Interior Gateway Routing Protocol) is a network protocol that lets routers exchange information more efficiently than with earlier network protocols.Continue Reading

• RSVP (Resource Reservation Protocol)

  RSVP (Resource Reservation Protocol) is a set of communication rules that allows channels or paths on the Internet to be reserved for the multicast (one source to many receivers) transmission of video and other high-bandwidth messages.Continue Reading

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

  PPPoE (Point-to-Point Protocol over Ethernet) is a specification for connecting multiple computer users on an Ethernet local area network to a remote site through common customer premises equipment, which is the telephone company's term for a modem ...Continue Reading

• foreign network

  In the Mobile Internet Protocol (Mobile IP), a foreign network is any network other than the home network to which a mobile device may be connected.Continue Reading

• UUCP (UNIX-to-UNIX Copy Protocol)

  UUCP (UNIX-to-UNIX Copy Protocol) is a set of UNIX programs for copying (sending) files between different UNIX systems and for sending commands to be executed on another system.Continue Reading

• sliding windows (windowing)

  Sliding windows, a technique also known as windowing, is used by the Internet's Transmission Control Protocol (TCP) as a method of controlling the flow of packets between two computers or network hosts.Continue Reading

• foreign agent

  In Mobile Internet Protocol (Mobile IP), a foreign agent is a router serving as a mobility agent for a mobile node.Continue Reading

• Next Hop Resolution Protocol (NHRP)

  In a computer network, the Next Hop Resolution Protocol (NHRP) is a protocol or method that can be used so that a computer sending data to another computer can learn the most direct route (the fewest number of hops) to the receiving computer.Continue Reading

• Reverse Address Resolution Protocol (RARP)

  RARP (Reverse Address Resolution Protocol) is a protocol by which a physical machine in a local area network can request to learn its IP address from a gateway server's Address Resolution Protocol (ARP) table or cache.Continue Reading

• NAK (negative acknowledgment or not acknowledged)

  NAK is an abbreviation for negative acknowledgment or not acknowledged.Continue Reading

• round-trip time (RTT)

  Round-trip time (RTT), also called round-trip delay, is the time required for a signal pulse or packet to travel from a specific source to a specific destination and back again...(Continued)Continue Reading

• FireWire

  FireWire is Apple Computer's version of a standard, IEEE 1394, High Performance Serial Bus, for connecting devices to your personal computer.Continue Reading

• HomeRF (home radio frequency)

  HomeRF (for home radio frequency) is a home networking standard developed by Proxim Inc.Continue Reading

• SDLC (Synchronous Data Link Control)

  (SDLC is also an abbreviation for systems development life cycle.Continue Reading

• IPX (Internetwork Packet Exchange)

  IPX (Internetwork Packet Exchange) is a networking protocol from Novell that interconnects networks that use Novell's NetWare clients and servers.Continue Reading

• spanning tree protocol (STP)

  Spanning tree protocol (STP) is a Layer 2 network protocol used to prevent looping within a network topology. The protocol allows two bridges to exchange information for only one bridge to handle a given message sent between two computers within the...Continue Reading

• Dynamic Source Routing (DSR)

  Dynamic Source Routing (DSR) is a self-maintaining routing protocol for wireless networks. The protocol can also function with cellular telephone systems and mobile networks with up to about 200 nodes. A Dynamic Source Routing network can configure ...Continue Reading

• GARP (Generic Attribute Registration Protocol)

  GARP (Generic Attribute Registration Protocol) is a local area network (LAN) protocol that defines procedures by which end stations and switches can register and de-register attributes, such as network identifiers or addresses, with each other...Continue Reading

• policy-based networking

  Policy-based networking is the management of a network so that various kinds of traffic - data, voice, and video - get the priority of availability and bandwidth needed to serve the network's users effectively.Continue Reading

• NBMA (non-broadcast multiple access)

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

• Nagle's algorithm

  Named for its creator, John Nagle, the Nagle algorithm is used to automatically concatenate a number of small buffer messages; this process (called nagling) increases the efficiency of a network application system by decreasing the number of packets...Continue Reading

• 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