SNAX Connection Manager (SNAX/CM) Manual

Glossary
Glossary–6 097842 Tandem Computers Incorporated
PSDN. Packet-switched data network.
pseudocontroller. A dummy controller, not actual hardware but part of the operating
systems software, that simulates the functions of a real controller (such as designating
a primary or secondary line). When SNAX/XF acts as an access method, it does not
access an actual controller but instead uses $SSCP (the SNAX/XF service manager) as
a pseudocontroller.
PVC. Permanent virtual circuit.
PU. See physical unit.
QLLC. Qualified Logical-Link Control protocol.
query status. A request for the current connection status. Query status also returns
other pertinent information about a connection such as the alias LU name when a line
is connected.
remote passthrough. Any passthrough session that spans two or more Tandem nodes.
return code. A value returned at the completion of a command, indicating whether the
command was successful and, if not, the reason for failure.
ring. A network topology in which stations are connected to one another in a closed
logical circle.
ring station. The instance of a MAC sub-layer in a node attached to the ring. The
station enables connections to the ring, and the operation of Token-Ring protocols
such as token handling, copying frames to and from the ring and directing frames to
the correct DLC link station.
routing . The process of selecting the correct circuit path for a message (across bridges
to other LAN segments).
SAP address. The address that identifies the service access point in a Token-Ring
network. See also service access point (SAP).
SCF. See Subsystem Control Facility.
SCP. See Subsystem Control Point.
SDLC. Synchronous data link control.
service access point (SAP). In OSI, the point at which the services of a layer are provided
to an adjacent layer. The service access point is indentified by a SAP address.
session. A temporary logical connection between two NAUs for the purpose of
exchanging data and control information in accordance with ground rules that have
been agreed upon for that exchange. A session can be activated, tailored to provide
various protocols, and deactivated, as requested.
site update tape (SUT). The means by which Tandem software is distributed to all user
sites.
SNA. Systems Network Architecture.