CCNA 1: Ch. 4 Vocab

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CCNA 1: Ch. 4 Vocab
2012-06-19 14:16:29

CCNA 1: Ch. 4 Vocab
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  1. flow control
    The management of data flow between devices in a network.

    Used to avoid to much data arriving before a device can handle it, causing data overflow.
  2. control data
    Data that directs a process. A flag in a data-link frame is an example of control data.
  3. IANA
    Internet Assigned Numbers Authority

    An organization that assigns the numbers important to the proper operation of the TCP/IP protocol and the Internet, including assigning globally unique IP addresses.
  4. well-known ports
    • Used by TCP and UDP, with values between 0 - 1023
    • these ports are allocated by high-privilege processes.

    Used so that all clients know the correct port number to connect to.
  5. registered ports
    • Using values between 1024 - 49,151
    • these numbers are equivalent to well-known ports in concept,

    but they are specifically used for non-privileged application processes.
  6. dynamic or private ports
    TCP & UDP ports that range from 49152 - 65535 and are not used by any defined server applications.
  7. URG
    a 1-bit flag in the TCP header used to indicate that the receiving host should notify the destination process to do urgent processing.
  8. ACK
    a 1-bit flag in the TCP header that indicates that acknowledgment field is valid.
  9. PSH
    a 1-bit flag in the TCP header that is used to request to the higher layers for immediate delivery of the packet.
  10. RST
    a 1-bit flag in the TCP header that is used to request that a connection be re-established.
  11. SYN
    a 1-bit flag in the TCP header used to indicate the initial value of the sequence number.

    Flag is only set in the first two segments of the three-way TCP connection establishment sequence.
  12. 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 done by inserting the FIN flag in the flag field found in the TCP segment.
  13. acknowledgment
    a notification sent from one network device to another to confirm that some event (like a receipt of a message) has occurred.
  14. window size
    As filed in the TCP header that is set in a sent segment, signifies the maximum amount of unacknowledged data the host is willing to receive before the other sending host must wait for an acknowledgment.

    Used for flow control.