Ch. 4 Key Terms

  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.
Card Set
Ch. 4 Key Terms
Chapter Four OSI Transport Layer Network Fundamentals, CCNA Exploration Companion Guide