Configuring and Managing Host-Based X.25 Links - Edition 6 (36939-90057)

Glossary
duplex
Glossary
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duplex Transmission method that allows two-way
communication. If both ends of the transmission link
can transmit simultaneously, it is called full duplex.
If only one end can transmit at a time, it is
half-duplex transmission.
dynamic configuration The ability to make DTS
configuration changes using NMMGR without
rebooting the HP 3000 system.
entry priority The ranking that identifies the most
desirable route used to reach a given remote node
from a given local node in a point-to-point network.
environment A session that is established on a
remote node.
escape from data transfer character A
character that allows a user who is connected to a
host system through the DTC to break that
connection and return to the DTC switching user
interface. The default is
[CTRL]-K
. This character is
used only on networks managed by the OpenView
Windows Workstation.
escape sequence A sequence of characters
beginning with the escape character and followed by
one or more other characters, used to convey control
directives to printers, plotters, or terminals.
Ethernet A Local Area Network system that uses
baseband transmission at 10 Mbps over coaxial
cable. Ethernet is a trademark of Xerox Corporation.
event log One of three circular files stored on the
OpenView workstation containing lists of all
significant events reported by the DTCs for which it
is the owner; that is, whose operating
software/configuration it has downloaded.
extended packet sequence numbering One of
the optional network subscribed facilities that
provides packet sequence numbering using modulo
128. If not subscribed, modulo 8 is used.
facility An optional service offered by a packet
switching network’s administration and requested
by the user either at the time of subscription for
network access or at the time a call is made. Also
known as user facility.
facility set A facility set defines the various X.25
connection parameters and X.25 facilities that can
be negotiated for each virtual circuit on a per-call
basis.
fast select An optional packet-switching network
facility by which user data may be transmitted as
part of the control packets that establish and clear a
virtual connection.
FCS Frame Check Sequence. A sequence of bits
generated by X.25 at level 2 that forms part of the
frame and guarantees the integrity of its frame’s
content. The FCS is also used by the IEEE 802.3
protocol to check the validity of frames.
file equation Assignment statement used to
associate a file with a specific device or type of device
during execution of a program.
file number Unique number associated with a file
when the file is opened. The file number is returned
in the FOPEN or HPFOPEN call used to open the
file. It can be used to access that file until the file is
closed.
file specification The name and location of a file.
The full specification for a file includes the file name,
group, and account.
file system The part of the operating system that
handles access to input/output devices (including
those connected through the DTC), data blocking,
buffering, data transfers, and deblocking.
flow control A means of regulating the rate at
which data transfer takes place between devices to
protect against data overruns.
flow control negotiation One of the network
subscribed facilities, selected at subscription time.
This facility allows the flow control parameter to be
negotiated at call set-up time, as opposed to having a
predefined value.
formal file designator Name that can be used
programmatically or in a file equation to refer to a
file.
FOS Fundamental Operating System. The
programs, utilities, and subsystems supplied on the
master installation tape that form the basic core of
the operating system.