OSI/TS Configuration and Management Manual

Glossary
OSI/TS Configuration and Management Manual—424831-001
Glossary-8
Nowait mode.
Nowait mode. The mode in which the called procedure initiates an I/O operation but does
not wait for it to complete before returning control to the caller. To have the called
procedure wait for the completion of the operation, the application calls a separate
procedure (AWAITIOX for the OSI/TS programmatic interface; MFM_AWAITIOX_ for
the OSI/AS interface).
NSAP (network service access point). The logical point at which Network Layer services
are provided by the Network Layer entity to the Transport Layer entity.
NSAP address. The global, network-unique address of an end system’s network service
access point, through which Network Layer services are provided.
NSP (network service provider) process. A process in the OSI subsystem that performs
service and protocol functions for the Network Layer and, for LANs, some functions of
the Data Link Layer. NSP processes are provided by the underlying X25AM and TLAM
subsystem (for D-series and pre-G06 releases, or PAM subsystems for G06 and above
releases).
Object-name template. In DSM, a name that stands for more than one object. Such a name
includes one or more wild-card characters, such as * and ?.
OSI (Open Systems Interconnection). A set of standards used for the interconnection of
heterogeneous computer systems, thus providing universal connectivity.
OSI address. The address of an object on the network, which includes the network service
access point (NSAP). transport selector (TSEL), session selector (SSEL), and
presentation selector (PSEL).
OSI manager process. A process in the OSI/AS subsystem that performs subsystem
management functions, including management of the Management Information Base
(MIB). There is one OSI manager process per OSI/AS subsystem.
OSI Reference Model. A communications architecture, adopted by the ISO in 1984, that
includes seven layers that define the functions involved in communications between two
systems, the services required to perform these functions, and the protocols associated
with these services.
OSI Subsystem. One OSI manager process controls one or more TAPS and TSP processes.
The OSI manager processes communicates with NSP processes but do not control them.
The OSI manger, TAPS, TSP, NSP processes can be on the same or different nodes
within the same Expand network.
PAM (Port access method). For G6x series. A Compaq product that implements, for LANs,
the services of the Data Link Layer and layers below.
Passive multiplexing. A feature of Compaq OSI/TS that can help conserve X25AM
resources by allocating one single X25AM SU per local network address (X.25 port and
local NSAP address) regardless of the number of concurring transport attach requests.