Troubleshooting Terminal, Printer and Serial Device Connections - Edition 4 (32022-90030)

Glossary 151
Glossary
PSS Packet-Switching System.
The national public PSN of the
United Kingdom.
PVC Permanent Virtual Circuit.
A permanent logical association
between two physically separate
DTEs that does not require call
set-up or clearing procedures.
Q bit See Packet Exchange
Protocol.
Q
Q bit Qualified bit. When set in
DATA packets the Q bit signifies
that the packet’s user data is a
control signal for the remote
device, not a message for its user.
QuickVal A software program
that tests whether Network
Services are operating correctly
between nodes.
R
RDBA Remote Data Base Access.
A network service that allows
users to access data bases on
remote nodes.
reachable network A network
that can be accessed (with
additional internet hops possibly
required) by a particular gateway.
remote connect device An
asynchronous device that is
indirectly connected to a DTC
through a modem and telephone
hook-up or through a PAD.
remote node Any network node
that is physically separate from
the node you are currently using
or referring to.
retransmission count (N2)
The maximum number of times a
frame will be retransmitted
following the expiration of the
Retransmission Timer, T1.
retransmission count (T!) The
length of time that a transmitter
will wait for an acknowledgment
from a destination address before
attempting to retransmit a frame.
When choosing this value, factors
like the line speed and maximum
frame size should be taken into
account.
RFA Remote File Access. A
network service that allows users
to access file and devices on
remote nodes.
routing The path that packets or
fragments of a message take
through a network to reach a
destination node.
RMP Remote Maintenance
Protocol. HP proprietary protocol
used in DTC management.
RPM Remote Process
Management. A network service
that allows a process to
programmatically initiate and
terminate other processes
throughout a network from any
node on the network.