Initiates an XID exchange between the system specified by node-id
    and the client.

    query  [node node-id] mop client client-name [,sap octet]

    The Address and Circuit information is required.  If the Client
    cannot provide that information, then it must be supplied in the
    command.

    query [node node-id] mop client client-name -
          address lan-address, -
          circuit circuit-name [,sap octet]

    The optional SAP argument specifies the Service Access Point on
    the target system to which the XID message is to be sent.  SAP is
    an octet (00-FF).  The default SAP is 00.

    The query requester function must be enabled on the MOP Circuit
    to perform the query operation.  You may enable this function
    using:

    enable mop circuit circuit-name function {query requester}

    Examples:

    query mop client lamchp -       ! Client provides the Circuit.
          address 08-00-2b-34-09-FF

    query mop client lamchp -       ! Client provides the Address.
          circuit csmacd-1

1  –  Exception Messages

 o  data link error

    An error was reported by the Data Link layer.  Ascertain that
    the query requester function is enabled on the MOP circuit.

 o  unrecognized client

    There is no client with the specified identification.

 o  unrecognized circuit

    There is no circuit with the specified identification.

 o  timeout

    Operation has timed out on the loop command.

 o  entity class not supported (OpenVMS)

    MOP is not registered with EMAA.  The NET$MOP process is
    probably not started.  For instructions on how to restart
    the MOP process, refer to HELP NETWORK_MANAGEMENT MOP.