The HDLC module implements one of the protocols in the Data Link
    layer. The HDLC (High-level Data Link Control) protocol is intended
    to cover a wide range of applications; for example, one-way, two-way
    alternate or two way simultaneous data communication between
    data stations which are usually buffered, including operations on
    different types of data circuits; for example multipoint/point-
    to-point, duplex/half-duplex, and switched/non-switched. This
    implementation uses HDLC to offer reliable communication at the
    Data Link layer for point-to-point synchronous data lines over a
    wide area network link. The HDLC module typically runs as a Data
    Link module under the CLNS Network protocol.

                               NOTE

    For Tru64 UNIX, the WAN Device Drivers are provided as an
    installable subset within the product HP Wide Area Network Support
    for Tru64 UNIX.  You must install this subset before you can refer
    to HDLC module entities in an NCL command.

    For OpenVMS, you must install the WAN Device Drivers from the
    HP X.25 for OpenVMS product before you can refer to the HDLC
    module entities in an NCL command.

1  –  Subentities

    The entity hierarchy of the HDLC module is:

    Node___HDLC____Link____Logical_Station
                 |
                 |_Port

    The HDLC entity is the top-level entity in the hierarchy of
    entities belonging to the HDLC module.

    An HDLC LINK entity is associated with a port of the supporting
    physical layer module. It contains attributes common to local
    HDLC operations for all logical stations on the line. The link-
    name refers to the HDLC link managed by this command.

    The HDLC LINK LOGICAL STATION entity controls the characteristics
    of an HDLC logical station. There is one station for each remote
    termination of a line associated with the HDLC link. The link-
    name is the link entity within the HDLC module and the logical-
    station-name refers to the logical station managed by this
    command.

    The HDLC PORT entity represents one end of an HDLC connection.
    The entity maintains information about that link. Ports are
    created and deleted automatically when a client of HDLC uses the
    link. The port-name refers to the port managed by this command.