osi
*Conan The Librarian (sorry for the slow response - running on an old VAX)
|
Library /sys$common/syshlp/net$mgmt_help.hlb osi *Conan The Librarian (sorry for the slow response - running on an old VAX) |
|
This module implements the OSI Connection-Oriented Transport Protocol
specification International Standard ISO 8073; and for DEC OSF/1, the
Connectionless-Mode Transport Service Protocol International Standard ISO
8602. These protocols implement the OSI Reference Model Transport Layer 4.
These protocols, as well as the NSP protocol, implement the transport
protocols in the Digital Network Architecture.
The entities that constitute the OSI Transport module are listed below. The
indention indicates the hierarchical relationships between the entities.
OSI Transport
Application
Port
Template
Local NSAP
Remote NSAP
The Connection-Oriented Transport Service COTS provides transparent and
reliable transfer of data between Transport Service users. It operates over
the Network layer, and employs end-to-end protocols that enhance the inherent
characteristics of the underlying network service.
The protocol is structured to produce protocol classes that minimize the
possible incompatibilities and implementation costs. A protocol class is
selected for a particular transport connection, based on the characteristics
of the network service to be used, the requirements of the Transport Service
user, and the availability of classes at the remote Transport Service
provider.
This module implements class 0, class 2, and class 4 of the COTS protocol.
Class 0 is the simplest class. It sets up a network connection for each
transport connection requested, and assumes that the network connection does
not make errors. The transport protocol does neither sequencing nor flow
control, as it relies on the underlying network layer to perform everything
correctly.
Class 2, like class 0, is designed to be used over reliable networks. It
differs from class 0 in that two or more transport connections may be
multiplexed over the same network connection.
Class 4, the most complex of the protocols, is designed to work over
unreliable Network Services. It can handle the error detection and recovery
of lost transport packets. These packets are called TPDUs Transport
Protocol Data Units. Class 4 runs over either CLNS or CONS. Classes 0 and
2 run only over CONS.
The Routing module provides a connectionless network service CLNS; for more
information, refer to the Routing chapter.
The X.25 Access module, if configured into the system, provides a reliable
connection-oriented network service CONS.
The OSI Transport entity is the top-level entity in the hierarchy of
entities belonging to the OSI Transport module.
Additional Information (explode) :
|
|
