Agilent Technologies J3919A, J3972A manual Half-duplex, Header Error Control HEC, Idle Cell

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.

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