OSI/TS SCF Reference Manual

Glossary
OSI/TS SCF Reference Manual—424832-001
Glossary-6
OSI/AS
OSI/AS. A communications subsystem that provides the services of the Open Systems
Interconnection (OSI) Session Layer and Presentation Layer and the called address
component of the Application Layer, allowing Compaq applications to communicate
with other applications in a multivendor environment.
OSI/FTAM. A communications subsystem that provides file transfer, access, and
management (FTAM) functions across a heterogeneous network, in conformance with
the International Standards Organization (ISO) FTAM standard. Compaq OSI/FTAM
supports the transfer of files between Himalaya S-series servers and other kinds of
computers. It also lets users on the Himalaya S-series server manage and operate on
remote files and lets users on other kinds of systems manage and operate on files on the
Himalaya S-series server.
OSI/MHS. A communications subsystem that is a message handling system in conformance
with the International Telecommunications Union–Telecommunications (ITU–T)
X.400
Recommendation. It supports the exchange of messages among diverse applications,
such as electronic mail (email) and electronic data interchange (EDI), across Open
Systems Interconnection (OSI) networks.
OSI/MHS Gateway Programmatic Interface (GPI). The Compaq implementation of the
X.400 Gateway application program interface (API). It provides a programmatic
interface to OSI/MHS
at the Message Transfer Agent (MTA) boundary.
OSI/TS. A communications subsystem that provides Open Systems Interconnection (OSI)
layer 4 (Transport Layer) services to OSI/AS applications or to user applications
needing direct access to OSI Transport Layer services. Compaq OSI/TS implements the
Connectionless Network Layer Protocol (CLNP) for use over local area networks
(LANs) or (optionally) X.25 packet-switched data networks (PSDNs). It provides a
uniform interface to applications in wide area network (WAN) and LAN environments,
using network and data-link services provided by the ViewPoint
for D-series systems or
the Port Access Method (PAM) for G-series systems.
passive multiplexing. A feature of OSI/TS
that can help conserve ViewPoint 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.
Physical Layer. Layer 1 in the Open Systems Interconnection (OSI) Reference Model
. This
layer establishes the actual physical connection between the network and the computer
equipment. Protocols at the Physical Layer include rules for the transmission of bits
across the physical medium and rules for connectors and wiring.
Port Access Method (PAM). A Compaq communications subsystem that provides an
independent interface to allow applications access to token-ring or Ethernet local area
networks (LANs) on Himalaya S-series servers. The PAM subsystem provides a port
interface that applications can use by making file-system procedure calls. The PAM
subsystem implements, for LANs, the services of the Data Link Layer
and layers below.
PAM replaces the Tandem LAN Access Method (TLAM) for G6x series systems.
port address. For ViewPoint
lines, the logical port number used to specify the address of the
connection to the X.25 network
. For the Tandem LAN Access Method (TLAM) (for