PAM Programming Manual

Glossary
PAM Programming Manual—142482
Glossary-6
service data unit (SDU)
service data unit (SDU). The information passed across the network to a peer entity and then
up to the next layer.
sensitive command. One that can be issued only by a user with a SUPER ID, by the owner
of the subsystem, or by a member of the group of the owner of the subsystem. For
Tandem communications subsystems, the sensitive commands can change the state or
configuration of objects, start or stop tracing, or change the values of statistics counters.
See also nonsensitive command
.
service. A set of primitives (operations) that a Open Systems Interconnection (OSI) layer
provides to the layer above it. The service defines what operations the layer can perform
for its users, but not how these operations are implemented.
SLSA subsystem. See ServerNet LAN systems access (SLSA) subsystem
.
SNAP (Subnetwork Access Protocol). In order to run the TCP/IP or NonStop IPX/SPX
protocol suites over IEEE networks, the Subnetwork Access Protocol (SNAP) defines
the interface between the IP Layer or IPX Layers, respectively, and the LLC Layer. The
interface is accomplished through the use of an extension of the LLC header that
contains a predefined Service Access Point (SAP) for use in the Source SAP (SSAP)
and the Destination SAP (DSAP) fields of the LLC header.
START. A sensitive SCF command that initiates the operation of an object. The successful
completion of the START command leaves the object either in a STARTED or
STARTING state.
STARTED summary state. A state in which an object is able to perform its normal data
communications functions. The flow of information, either to or from the object, is not
restricted in any way. Sessions can be established with the object. The object is available
for use by programs executing in either the Tandem system or workstations on an
attached LAN.
STATS. A nonsensitive SCF command that displays statistical information for the specified
object.
STATUS. A nonsensitive SCF command that displays status information about an object,
such as the dynamic state, the last error, and the modifiable values of the specified
object. STATUS also displays specific PAM subsystem attributes and values.
STOP. A sensitive SCF command that terminates the activity of an object. It deletes all
connections to and from the object in a nondisruptive manner.
STOPPED summary state. The state of an object added to the configuration but not
currently initialized.
subnet. The point of connection between the Tandem NonStop TCP/IP process and the
ServerNet LAN systems access (SLSA) logical interface (LIF). The data coming from or
going to an Ethernet LAN goes through a subnet.