Introduction to Networking for NonStop S-Series Servers

Glossary
Introduction to Networking for HP NonStop S-Series Servers—520670-005
Glossary-21
SNA
SNA. See Systems Network Architecture (SNA).
SNMP. See Simple Network Management Protocol (SNMP).
socket. A logical connection between two applications across a Transmission Control
Protocol/Internet Protocol (TCP/IP) network.
stack. A layered organization of protocol functions, in which entities at a given level use
services at the next lower level. Application-oriented functions are near the top of the
stack, and communications-oriented functions are near the bottom of the stack.
subarea. A division of an IBM Systems Network Architecture (SNA) network for addressing
purposes. A subarea consists of a subarea node, which must be of type 4 or 5, and
the resources it controls. The subarea has an address unique in the network, and
addresses are unique within the subarea.
subdevice. A recipient of requests within a subsystem. A subdevice often corresponds to a
real external entity, such as a station on a multipoint line.
subsystem. A process or collection of processes that give users access to a set of related
resources or services. A subsystem typically controls a cohesive set of objects.
Subsystem Control Facility (SCF). A part of DSM, it is used to provide a common,
interactive management interface for configuring, controlling, and collecting information
from HP data communications products.
Subsystem Control Point (SCP). A network management process for receiving and
redistributing the messages that SCF sends to certain data communications
subsystems.
switch enclosure. An enclosure provided by HP for housing the subcomponents of a
NonStop Cluster Switch. These subcomponents include the ServerNet II Switch, the
AC transfer switch, and the uninterruptible power supply (UPS). A switch enclosure
resembles, but is half the height of, a standard NonStop S-series system enclosure.
switched line. Refers to circuit-switched networks, such as a public telephone network. A
communications line in which the connection between the computer and a remote
station is established by various circuit switches. Sometimes called a dial-up line.
synchronous data transmission. A method of data transmission whereby data is sent and
received in blocks (or frames) instead of one character at a time. Synchronous data
transmission requires synchronization characters or flags in the transmission. Contrast
with asynchronous data transmission.
system process. (1) A privileged process that comes into existence at system-load time
and exists continuously for a given configuration for as long as the processor remains
operable. (2) A configuration operating system process, such as the memory manager,
the monitor, and the input/output (I/O) control processes. Contrast with user process.