A client entity to be used to provide the LAN address for
    this loop operation.   If an Address is not supplied in the
    command on a LAN circuit, then the Client argument is
    required so the address information can be obtained from the
    MOP Client database.

    loop  [node node-id] mop circuit circuit-name -
          client client-name [,optional arguments...]

    Optional arguments for this loop mop circuit command are:
    Assistance Type, Assistant Address, Assistant System, Count,
    Format, and Length.

    Example:

    loop mop circuit csmacd-1 -
         client lamchp          ! Client gives default loop Address