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Technical Standard: Networking Services (XNS), Issue 5.2 Draft 2.0
Copyright © 1999 The Open Group
Glossary
abortive release
An abrupt termination of a transport connection, which may result
in the loss of data.
asynchronous mode
The mode of execution in which transport
service functions do not wait for specific
asynchronous events to occur before returning control to the user, but instead
return immediately if the event is not pending.
CL
Connectionless (a deprecated synonym for "connectionless-mode").
CO
Connection-oriented (a deprecated synonym for "connection-mode").
connection establishment
The phase in connection-mode that enables two transport users to create
a transport connection between them.
connection-mode
A mode of transfer where a logical link is established between two endpoints.
Data is passed over this link by a sequenced and reliable way.
connectionless-mode
A mode of transfer where different units of data are passed through the
network without any relationship between them.
connection release
The phase in connection-mode that terminates a previously established
transport connection between two users.
datagram
A unit of data transferred between two users of the connectionless-mode
service.
data transfer
The phase in connection-mode or connectionless-mode that supports the
transfer of data between two transport users.
DNS
The Domain Name System defined in RFC 1035.
This system provides translation between host names and Internet
addresses.
EM
Event Management
expedited data
Data that are considered urgent. The specific semantics of
expedited data are defined by the transport provider that provides the
transport service.
ETSDU
Expedited Transport Service Data Unit
expedited transport service data unit
The amount of expedited user data, the identity of which is preserved
from one end of a transport connection to the other (that is, an
expedited message).
FQDN
Fully-qualified domain name.
host byte order
The implementation-dependent byte order supported by the local host machine
(see the Glossary entry for "Network Byte Order").
Functions are provided to convert 16 and 32-bit values between network and
host byte order (see
htonl()).
initiator
An entity that initiates a connection request.
ISO
International Organization for Standardization
legacy
An item marked "LEGACY" in this specification means that
it is being retained for compatibility with older
applications, but has limitations which makes it inappropriate for
developing portable applications.
New applications should use alternative means of obtaining equivalent
functionality.
network byte order
The byte order in which the most significant byte of a multibyte
integer value is transmitted first. This byte order is the standard
byte order for Internet protocols.
network host database
A database whose entries define the names and network addresses
of host machines. See
gethostent().
network net database
A database whose entries define the names and network numbers of
networks. See
getnetent().
network protocol database
A database whose entries define the names and protocol numbers of
protocols. See
getprotoent().
network service database
A database whose entries define the names and local port numbers of
services. See
getservent().
orderly release
A procedure for gracefully terminating a transport connection with no
loss of data.
OSI
Open System Interconnection
responder
An entity with whom an initiator wishes to establish a transport connection.
socket
A communications endpoint associated with a file descriptor that
provides communications services using a specified communications
protocol.
SVID
System V Interface Definition
synchronous mode
The mode of execution in which transport service functions wait for specific
asynchronous events to occur before returning control to the user.
TC
Transport Connection
TCP
Transmission Control Protocol
TLI
Transport Level Interface
transport address
The identifier used to differentiate and locate specific transport endpoints
in a network.
transport connection
The communication circuit that is established between two transport
users in connection-mode.
transport endpoint
The communication path, which is identified by a file descriptor,
between a transport user and a specific transport provider.
A transport endpoint is called passive before, and active after,
a relationship is established,
with a specific instance of this
transport provider, identified by the TSAP.
transport provider identifier
A character string used by the
function to identify the transport service provider.
transport service access point
A TSAP is a uniquely identified instance of the transport provider.
A TSAP is used to identify a transport user on a certain endsystem.
In connection-mode, a single TSAP may have more than one connection
established to one or more
remote TSAPs;
each individual connection then is identified
by a transport endpoint at each end.
transport service data unit
A unit of data transferred across the transport service with boundaries
and content preserved unchanged.
A TSDU may be divided into sub-units
passed between the user and XTI.
The T_MORE flag is set in all but
the last fragment of a TSDU sequence
constituting a TSDU.
The T_MORE flag implies nothing about
how the data is handled and passed
to the lower level by
the transport provider, and how they are delivered to the remote user.
transport service provider
A transport protocol providing the service of the transport layer.
transport service user
An abstract representation of the totality of those entities within a single
system that make use of the transport service.
TSAP
See Transport Service Access Point
TSDU
See Transport Service Data Unit
UDP
User Datagram Protocol
user application
The set of user programs, implemented as one or more process(es)
in terms of UNIX
semantics, written to realise a task, consisting of a
set of user required functions.
XTI
X/Open Transport Interface
XEM
X/Open Event Management Interface