TCP/IP (Parallel Library) Migration Guide

Glossary
HP NonStop TCP/IP (Parallel Library) Migration Guide—522272-003
Glossary-10
SMTP
SMTP. See Simple Mail Transfer Protocol (SMTP).
SNAP. See Subnetwork Access Protocol (SNAP).
SPI. See Subsystem Programmatic Interface (SPI).
subnet address. An extension of the Internet protocol (IP) addressing scheme that allows a
site to use a single IP address for multiple physical networks. A subnetwork address is
created by dividing the local part of an IP address into a subnetwork number
(identifying a particular subnetwork) and a host number (uniquely identifying the host
system within the subnetwork). The terms subnetwork address and subnet
address are used interchangeably.
subnetwork. One or more intermediate systems that provide relaying and through which
end open systems can establish network connections.
Subnetwork Access Protocol (SNAP). To run the TCP/IP protocol suite over IEEE
networks, the Subnetwork Access Protocol (SNAP) defines the interface between the
IP layer 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.
subsystem. (1) The software and/or hardware facilities that provide users with access to a
set of communications service. (2) For DSM, a program or set of processes that
manages a cohesive set of objects. Each subsystem has a process through which
applications can request services by issuing commands defined by that subsystem; in
some cases, this process is the entire subsystem. Many subsystems also have
interactive interfaces.
Subsystem Control Facility (SCF). An interactive interface for configuring, controlling, and
collecting information from a subsystem and its objects. SCF enables you to configure
and reconfigure devices, processes, and some system variables while your NonStop
S-series server is online.
Subsystem Control Point (SCP). The message router for Subsystem Control Facility
(SCF). There can be several instances of this process. Using the Subsystem
Programmatic Interface (SPI), applications send each command for a subsystem to an
instance of the SCP process, which in turn sends the command to the manager
process of the target subsystem. SCP also processes a few commands itself. It
provides security features, version compatibility, support for tracing, and support for
applications implemented as process pairs.
Subsystem Programmatic Interface (SPI). A set of procedures and associated definition
files and a standard message protocol used to define common message-based
interfaces for communication between management applications and subsystems. It
includes procedures to build and decode specially formatted messages; definition files
in Transaction Application Language (TAL), COBOL85, and HP Tandem Advanced
Command Language (TACL) for inclusion in programs, macros, and routines using the