This module implements the OSI Connection-Oriented Transport
    Protocol specification (International Standard ISO 8073); and
    the Connectionless-Mode Transport Service Protocol (International
    Standard ISO 8602) for Tru64 UNIX. For OpenVMS, this module also
    implements RFC1006 and RFC1006 Extension. 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 OSI Transport Protocol permits communication between
    DECnet-Plus systems and other vendors' systems that also implement
    the OSI Transport Protocol.  You can set up OSI Transport
    connections:

    o  Between two systems on the same ISO 8802-3 LAN.

    o  Between two systems that are connected, either directly
       or via an X.25 connection.

    o  Between two systems that are connected directly by an X.25
       point-to-point link.

    o  Between two systems on different subnetworks, where the
       linking subnetworks might mix technologies.

    o  Between two systems that are connected via TCP/IP.

    Refer to CONNECTION_PHASES below for a description of the three
    phases of an OSI Transport connection.

    The OSI Transport Protocol conforms to the ISO 8072 Service
    Definition and the ISO 8073 Protocol Standard. They define
    OSI Transport Protocol classes 0, 2 and 4 (TP 0, TP 2, and TP 4).

    This protocol can use two types of ISO Network service:

    o  Connection-Oriented Network Service (CONS)

    o  Connectionless-Mode Network Service (CLNS)

    The Routing module provides a connectionless network service
    (CLNS).  The X.25 Access module, if configured into the system,
    provides a reliable connection-oriented network service (CONS).

    For Tru64 UNIX, any attributes that are specific to CONS will only
    be accessible if X.25/CONS has been installed and configured into
    the system. See X.25/CONS Configuration for more information. The
    Connectionless Transport Service, known as CLTS or CLTP, allows
    for the transfer of data between correspondent Transport Service
    users on a connectionless basis. The service provides for single-
    access data transfer for corresponding Transport Service users,
    without the overhead of establishing a connection. This protocol
    benefits those applications that require a one-time, one-way
    transfer of data toward one Transport Service user. CLTS runs
    over CLNS.

    The OSI transport conforms to the RFC1006 Standard and to the
    RFC1859 Standard.  They define how to implement ISO 8073 Transport
    Class 0 on top of TCP (RFC1006) and how to implement ISO 8073
    Transport Class 2 Non-use of Explicit Flow Control on top of TCP
    (RFC1859, once known as 1006 Extension). The network service used
    is provided by TCP.  These OSI over TCP/IP and DECnet over TCP/IP
    features require an installed TCP/IP product that supports the PWIP
    interface.

    Refer to NETWORK_SERVICES below for a table which shows the
    relationship between the transport protocols and the network
    services.

    Refer to PROTOCOL_CLASSES for a table describing the protocol
    classes, their functions, and which network service can be used.