OSI/TS SCF Reference Manual

Glossary
OSI/TS SCF Reference Manual—424832-001
Glossary-8
protocol control information (PCI)
protocol control information (PCI). Information exchanged between peer entities to
coordinate their joint operation within a specific layer.
protocol data unit (PDU). Information delivered as a unit between peer entities that contains
data and/or control and address information.
register request. A request made by APS, on behalf of an application, for the Open Systems
Interconnection (OSI) manager process to configure the resources necessary for that
application to communicate using the OSI/AS subsystem. A register request is generated
as a result of a call to APS_ASSOC_CONNECTREQ_ or APS_ASSOC_ATTACH_.
release token. One of the four types of Session Layer
tokens that are associated with
functional units.
Request primitive. A primitive issued when a service user (entity) wants the service to do
some work. This is one of four types of service primitives.
Response primitive. A primitive issued when a service user (entity) wants to respond to an
event. This is for confirmed services only. This is one of four types of service primitives.
resynchronization. The Session Layer
feature that allows an application to reset a
connection to a defined state after a problem has occurred. This action includes
reassignment of tokens, setting the synchronization point serial number to a new value,
purging all undelivered data, or going back to a defined previous synchronization point.
SCF. See Subsystem Control Facility (SCF)
.
sensitive command. A Distributed Systems Management (DSM)
command that can be
issued only by a restricted set of users. For Compaq communications subsystems, the
sensitive commands are those that can change the state or configuration of objects, start
or stop tracing, or change the values of statistics counters. Compare nonsensitive
command.
ServerNet adapter. A customer-replaceable unit (CRU) that connects peripheral devices to
the rest of the system through a ServerNet bus interface (SBI). A ServerNet adapter is
similar in function to an I/O controller logic board (LB) and backplane interconnect card
(BIC) in Himalaya K-series servers.
service. A set of primitives (operations) that a layer provides to the layer above it. The
service defines what operations the layer can perform on behalf of its users, but not how
these operations are implemented. A service relates to an interface between two layers,
with the lower layer being the service provider and the upper layer being the service
user.
service access point (SAP). The access means by which a pair of communicating entities in
adjacent layers use or provide services.
service data unit (SDU). Information passed across the network to a peer entity and then up
to the next layer.