The optional Assistant Address argument specifies the
    LAN address of the node to be used as a loopback assistant.
    This argument is meaningful for LAN circuits only.

    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.

    Address information specifying the node to receive the
    loop is required for the loop mop circuit command.  If the
    Address argument is not specified in the command, then the
    Client argument must be specified so the address
    information can be obtained from the MOP Client
    database.

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

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

    Examples:

    loop mop circuit fddi-1 -
      address 08-00-2b-00-33-44, -
      assistant address aa-00-04-00-33-44, -
      assistance type receive

    loop mop circuit csmacd-1 -
      client foofoo, -     ! Client foofoo gives loop Address
      assistant address aa-00-04-00-33-44, -
      assistance type full