Agilent Technologies J3972A - Manual (Page 164)

144
Half-duplex
A form of communication where information can only travel one direction at a
time. See also Full-duplex.
Header
Information at the beginning of a cell, frame or packet normally used for
alignment, routing, operations or similar purposes.
Header Error Control (HEC)
The Header Error Control (HEC) is an 8-bit field and the fifth byte in the header
of an ATM cell. The HEC value is calculated from the first four bytes of the cell
header. If an error occurs in an ATM Cell header, it will be detected in the HEC
field. Cells with HEC errors that cannot be corrected are discarded by the
receiving node. The HEC field can also be used to determine the boundaries of a
packet for cell delineation.
Idle 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).
IEEE 802.3 standard
Part of the Institute of Electrical and Electronics Engineers 802 family of LAN
standards. The 802.3 standard defines the physical layer (layer 1) and part of the
data link layer (layer 2) of the ISO OSI reference model for a CSMA/CD LAN.
The IEEE 802.3 standard evolved from Ethernet, but the two networks are not
fully compatible with each other.
IEEE 802.5 Standard
Part of the Institute of Electrical and Electronics Engineers 802 family of LAN
standards. The 802.5 standard defines the physical layer (layer 1) and part of the
data link layer (layer 2) of the ISO OSI reference model for a Token-Ring LAN.
Information Field
A field of 44, 47, or 48 bytes in an ATM cell that carries service data.
Integration Period
Period used for statistics measurements.