The optional Assistant System argument specifies a MOP client
    entity, from which an assistant address can be obtained.
    This argument is meaningful for LAN circuits only.  The
    assistant address is the LAN address of the node to be used as
    the loopback assistant.

    The involvement of the assistant depends on the Assistance Type
    parameter. For assistance of type none (the default), no
    assistant is needed, and is ignored if specified. For other
    values, an assistant is required.

    An assistant can be specified either by including an Assistant
    Address or Assistant System argument in the command line, but
    not both.  If neither is provided, then an assistant is
    located by first sending a request to the loopback assistant
    multicast address.

    loop  [node node-id] mop client client-name -
      assistance type transmit-receive-or-full, -
      assistant system client-name [,optional arguments...]

    Address and Circuit information loop is required for the loop mop
    client command.  If the Client cannot provide default Address and
    Circuit information, then that information must be specified in
    the command.

    loop  [node node-id] mop client client-name -
      address lan-address, -
      circuit circuit-name, -
      assistance type transmit-receive-or-full, -
      assistant system client-name [,optional arguments...]

    Examples:

    loop mop client lamchp -     ! Lamchp gives Address and Circuit
      assistant system prkchp, - ! Client prkchp has Assistant Address
      assistance type full

    loop mop client foofoo -     ! Client foofoo gives default Circuit
      address 08-00-2b-44-33-5F, -
      assistant system barbar, - ! Barbar gives Assistant Address
      assistance type full