Agilent Technologies J3972A - Manual (Page 163)

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FIDF
FIDF is a 26-byte Transmission Header (TH) used for communication between
adjacent SNA subarea nodes, provided both support Explicit and Virtual Route
protocols, that use message sequencing.
Fill Cell
An empty or null ATM cell. This type of cell is a placeholder inserted into the
signal stream to occupy bandwidth not allocated to a service. Fill cells are in
either the Idle format (ITU-T) or Unassigned format (ATM Forum).
Flow Control
A method used to assure that the source does not overwhelm the destination by
sending data faster than it can be processed and absorbed.
Flash EPROM
EPROM that can be erased and reprogrammed while installed in a circuit.
Frame
A frame is a unit of information transferred on a network which contains control
and data information.
Full-duplex
A form of communication between two devices where packets flow in both
directions simultaneously. See also Half-duplex.
Gateway
A dedicated computer that is used to route frames from one dissimilar network to
another.
Generic Flow Control (GFC)
The Generic Flow Control is a 4-bit field in the first byte in the header of an ATM
UNI cell. The GFC field is used for flow control in various ATM applications.
Two modes of operation have been designed for the GFC field - Controlled and
Uncontrolled. A GFC field set to all zeros denotes no flow control or uncontrolled
transmission. A GFC field set to some non-zero value indicates a flow control
condition or controlled transmission.