The Loopback Application module allows a network manager to
    invoke a loopback test between applications on two nodes,
    thus testing all the supporting layers of the Digital Network
    Architecture.

    The Loopback Application module has two components:

    o  The loop access module, which initiates the loopback test

    o  The loop mirror module, which accepts connections from the
       remote loop access modules and mirrors any data sent to it
       back to the sender.

    The Loopback Application module has only one entity: the loopback
    application entity.  This loopback application entity describes
    features of the Loopback Application module which allows you to
    run a loopback test between two nodes or itself. The loopback
    application entity is created and deleted automatically with the
    node entity, and is always enabled.