Installing and Administering OSI Transport Services

148 Glossary
Glossary
SAS A station in an FDDI network
that connects to only one of the two
FDDI network rings. An SAS must
attach to the network through a
concentrator.
session interface An application
program interface to the OSI
session layer.
single attachment station See
SAS
SMT The ANSI FDDI standard
which manages connections with
the ring as well as station and ring
configuration.
station management See SMT
subnetwork A group of
computers that are a part of a
larger network and whose IP
address includes a subnetwork
number.
system administrator The
person who oversees system
maintenance and computer
operation.
topology The physical and logical
geometry governing placement of
nodes in a computer network. Also,
the layout of the transmission
medium for a network.
X/open transport interface See
XTI
XTI An application program
interface to the OSI transport
layer.
X.21 Defines the interface between
a computer and a public data
network where the access to the
network is made over synchronous
digital lines.
X.25 Defines the interface between
a computer and a packet switching
network.
X.400 The interface for electronic
messaging applications over a
network.
X.500 A distributed directory
interface allowing different
vendors to store and access
information on different systems.