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

Glossary
terminal type
Glossary
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terminal type A collection of characteristics that
cause a terminal connected to an MPE system to act
and react in a specified manner. You may configure a
terminal to use one of the system-supplied terminal
types, or you may create custom terminal types
using the workstation configurator.
ThinLAN A LAN media that conforms to the IEEE
802.3 Type 10 BASE 2 standard LAN.
ThinLAN 3000/iX Link Hardware and software
necessary to create a broadcast network, which uses
the IEEE 802.3 LAN cable to transmit messages to
all the nodes on the network. The messages are then
accepted only by the node or nodes to which they are
addressed. Also includes the ThickLAN and
StarLAN 10 options.
throughput class A value assigned to a given
virtual circuit that defines how many network
resources should be assigned to a given call. It is
determined by the access line speed, packet and
window sizes, and the local network's internal
mechanisms.
throughput class negotiation One of the network
subscribed facilities defined at subscription time.
This allows the user to negotiate the throughput
class at call set-up time.
timer (T3) Length of time that a link can remain in
an idle state. After the expiration of the timer, the
link is considered to be in a non-active,
non-operational state and is automatically reset.
The value should be chosen carefully. In particular, it
must be sufficiently greater than the retransmission
timer (T1) so that no doubt exists about the link's
state.
token ring A collection of data communication
systems sharing a common cable and
communicating by means of the IEEE 802.5
protocol. In a token ring network, access is
controlled by the passing of a token from node to
node. Outgoing messages are attached to the token
and passed with the token until they arrive at the
node to which they are addressed.
Token Ring 3000/iX Network Link Hardware
and software required to connect a HP 3000 Series
900 system to a token ring network.
topology The physical arrangement of nodes in a
network. Some common topologies are bus, star, and
ring.
Transmission Control Protocol TCP. A network
protocol that establishes and maintains connections
between nodes. TCP regulates the flow of data,
breaks messages into smaller fragments if necessary
(and reassembles the fragments at the destination),
detects errors, and retransmits messages if errors
have been detected.
Transpac The national public PSN of France.
transparent mode Data transfer scheme in which
only a limited number of special characters retain
their meaning and are acted on by the system. All
other characters are considered to be data and are
passed through with no control actions being taken.
transport, network Software that corresponds to
layers 3 and 4 of the OSI network architecture
model. The function of this software is to send data
out over the appropriate communications link, to
receive incoming data, and to route incoming or
outgoing data to the appropriate destination node.
TTUTIL Also known as the Workstation
Configurator. A program, TTUTIL.PUB.SYS, on the
HP 3000 that is used to create and modify terminal
and printer type files.
Tymnet A proprietary public data network in the
USA.
typeahead A facility that allows terminal users to
enter data before a read is actually posted to the
terminal.
UPS See uninterruptible power supply.
unacknowledged frame number (K) The
number of frames that can be transmitted without
receiving an acknowledgment from the destination
address. When this number (K) frame is reached, the
same K frames are retransmitted.
unedited mode See transparent mode.
uninterruptible power supply A hardware
device that protects equipment from power failures
and contains an internal storage battery to supply
reserve power.