Ch. 7 Key Terms

  1. nodes
    Data Link layer term describing a device connected to a network.
  2. physical network
    Connection of devices on a common media.

    AKA network segment
  3. logical network
    Group of devices associated by the arrangement of a hierarchical addressing scheme.

    Devices share common network portion of their Layer 3 addresses.
  4. network segment
    Part of a computer network that every device communicates with using the same physical medium.

    Can be extended by hubs or repeaters.
  5. NIC
    Network Interface Card

    Computer Hardware - used for LANs

    Allows a computer to connect to a networking cable it can then send and receive data over the cable at the direction of the computer.
  6. LLC
    Logical Link Control

    IEEE 802.2 standard that defines the upper sublayer of the Ethernet Layer 2 specifications (and other LAN standards).
  7. MAC
    Media Access Control

    Lower of the two sublayers of the IEEE standard for Ethernet.

    Defined by 802.3
  8. deterministic
    Indicates whether the performance of a device, attached to a particular type of LAN can be accurately predicted (determined).

    EX: Token Ring, LANs
  9. CSMA
    Carrier Sense Multiple Access

    Media access method in which transmitting node listens for a signal on the media before transmitting.

    Will wait to transmit if a signal is detected.
  10. carrier
    Signal on a medium used to support the transmission of data.

    • Data is "carried" over the medium by modulation
    • (combining data signal w/ carrier signal)
  11. collision

    Results of two nodes transmitting simultaneously.

    Causes damage to signals requiring them to be retransmitted.
  12. CSMA/CA
    Carrier Sense Multiple Access / Collision Avoid

    Mechanism used to regulate the transmission of data onto a network medium.

    Device requests right to send in order to avoid collisions.

    Used in 802.11 WLANs
  13. half duplex
    When communication can only be transmitted in one direction at one time.

    One station receives what the other transmits and must wait till completion to send the response.
  14. full duplex
    Communication that allows transmission and receipt at the same time.

    No collisions!
  15. physical topology
    Arrangement of the nodes in a network and the physical connections between them.

    Representation of how media is used to connect the devices.
  16. logical topology
    Map of the devices on a network representing how the devices communicate with each other.
  17. virtual circuit
    Logical connection between two devices in which the frames are passed between the devices.

    Independent of the physical structure and may be established through multiple physical devices.
  18. token passing
    Access method used with some LANs

    Devices access media in a controlled manner managed by a small frame called a token.

    Devices can only send when they have claimed the token.
  19. CRC
    Cycle Redundancy Check

    Type of hash function (one-way encryption) that is used to produce small, fixed-size checksum of a block of data, such as a packet or a computer file.

    CRC is computed & appended before transmission/storage and verified by the recipient to confirm nothing was changed during transmission.
  20. back-off
    Retransmission delay used with CSMA/CD when a collision occurs.

    Forces each sender that detected the collision to delay a random amount of time before attempting to retransmit.
  21. AID
    Association Identity

    Number used in the 802.11 header to specify the session between a wireless client and the access point.
  22. ARP
    Address Resolution Protocol

    Method for finding a host's hardware address (MAC) from its IPv4 Network Layer address.
Card Set
Ch. 7 Key Terms
Chapter Seven OSI Data Link Layer Network Fundamentals, CCNA Exploration Companion Guide