CCNA Vocabulary_E_F_G.txt

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CCNA Vocabulary_E_F_G.txt
2011-07-12 11:20:25
CCNA Vocab

CCNA Vocab E
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  1. electromagnetic interface
    • interface by magnetic signals caused by the flow of electricity. EMI can cause reduced data integrity and increased error rates on transmission channels. The physics of this process are that electrical current creates magnetic fields, which in turn cause other eletrical currents in nearby wires. The included electrical currents can interfere with proper operation of the other wire.
    • enable password unencrypted password used to allow access to privledge EXEC mode from IOS user EXEC mode.
  2. encapsulation
    the process by which a device adds networking heads and trailers to data from an application for the eventual transmission of the data onto a transmission medium.
  3. encode
    to change the energy levels transmitted over some networking medium to transmit bits over that medium.
  4. encryption
    the process of obscuring information to make it unreadable without special knowledge, somtimes referred to as scrambling. The process takes the data to be encrypted and applies a mathematical formula to it along with a secret number. The resulting value, which is called an encrypted packet is sent through a network
  5. end device
    a device such as a desktop or mobile device that is used by an end user.
  6. ethernet PHY
    the physical interface transceivers. It deals with Layer 1 (the physical layer, hence the PHY) of ethernet.
  7. extended star
    a network topology characterized by a central location connected to multiple hubs. In an extended star, these interconnected hubs may be connected to more hubs. It is essentially a hierarchical topology but typically is drawn with the central site in the center, with the rest of the topology radiating outward in all directions. This is sometimes called a hierarchical star.
  8. extranet
    part of a company's intranet that is extended to users outside the company
  9. fast ethernet
    • a common name for ethernet technology that operates at 100 mbps.
    • fault tolerance the design on networks that can continue to operate without interruption in the case of hardware, software or communications failures.
  10. fiber-optic cable
    physical medium that uses glass or plastic threads to transmit data. A fiber-optic cable consists of a bundle of these threads, each of which is capable of transmitting data into light waves.
  11. fiber optics
    the glass fibers inside certain cables over which light is transmitted to encode 0 and 1
  12. filtering
    in ethernet, the process performed by a bridge or switch when it decides that it should not forward a frame out another port
  13. FIN
    a 1-bit field in the TCP header that is used by a device that wants to terminate its session with the other device. This is done by inserting the FIN flag in the flag field found in the TCP segment
  14. firewall
    any combination of hardware device and/or software application designed to protect network devices from outside network users and/or malicious applications and files.
  15. flash
    a removable component that has memory space for storage. Used on the router or switch for storing the compressed operating system image.
  16. flooding
    a process used by a switch or bridge to forward broadcasts and unknown destination unicasts. The bridge/switch forwards these frames out all ports except the port on which the frame was received.
  17. flow control
    the management of data flow between devices in a network. It is used to avoid too much data arriving before a device can handle it, causing data overflow.
  18. forwarding
    In ethernet, the process performed by a bridge or switch when it decides that it should send a frame out another port.
  19. fragmentation
    the dividing of IP datagrams to meet the MTU requirement of a layer 2 protocol.
  20. frame
    the layer 2 pdu that has been encoded by a data link layer protocol for digital transmission. Some different kinds of frames are ethernet frames and PPP frames.
  21. full duplex
    • communication that allows receipt and transmission simultaneously. A station can transmit and receive at the same time. There are no collisions with full-duplex ethernet transmision.
    • gateway normally, a relatively general term that refers to dfifferent kinds of networking devices. Historically, when routers were created, they were called gateways
  22. gigabit ethernet
    ethernet that transmits data at 1,000,000,000 one billion bits per second.
  23. global configuration mod
    from the priviledged mode, you can enter the device's global caonfiguration mode. From global configuration mode, you can configure global parameters or enter other configuration submodes such as interface, router and line configuration submodes.
  24. globally scoped addresses
    unique addresses that are public domain addresses.
  25. goodputapplication-level throughput.
    It is the number of useful bits per unit of time from a certain source address to a certain destination, excluding protocol overhead and excluding retransmitted data packets.