The Maintenance Operations Protocol (MOP) module is located in the
    Application layer described by the Digital Network Architecture.
    MOP has a direct connection with the Data Link layer; thus, for
    certain functions, MOP can bypass the higher layers in the DNA
    protocol tower.  This is useful for nodes which do not (yet) have
    all the higher layers of DNA protocol towers installed. Functions
    provided by the MOP module include down-line loading, up-line
    dumping, and communications testing.

1  –  Subentities

    The entity hierarchy of MOP module is:

    Node___MOP____Circuit____Operation
                |          |
                |          |_Station
                |_Client

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

    A MOP CIRCUIT entity is a data link circuit on which MOP services
    are available. The status attribute functions specifies the
    services enabled on the circuit. The circuit-name refers to the
    circuit managed by this command.

    The MOP CIRCUIT OPERATION entities are created automatically
    by MOP for all operations, including those initiated by NCL
    action directives and those initiated by automatic load and dump
    service. They are deleted when the corresponding operation is
    complete.

    The MOP CIRCUIT STATION entities are created automatically by the
    Configuration Monitor. They are deleted when the circuit entity
    is deleted.  The Configuration Monitor function must be enabled
    on the MOP circuit for these entities to be created.  For more
    information, refer to HELP NETWORK_MANAGEMENT TOOLS
    CONFIGURATION_MONITOR.

    A MOP CLIENT entity is a set of default characteristics used
    by these MOP functions: dump/load server, load requester, loop
    requester, and console requester. When a command or a request
    for one of these services does not supply all of the required
    arguments, the values stored by the client are used to perform
    the operation. The client-name refers to the client managed by
    this command.