资料来源 : Free On-Line Dictionary of Computing

Upper Layer Protocol
     
         1. (ULP, or upper-layer protocol)
        Any {protocol} residing in {OSI} layers five or above.
     
        The {Internet} protocol suite includes many upper layer
        protocols representing a wide variety of applications
        e.g. {FTP}, {NFS}, {RPC}, and {SMTP}.  These and other network
        applications use the services of {TCP/IP} and other {lower
        layer protocols} to provide users with basic network services.
     
        2. A protocol higher in the OSI reference model than the
        current reference point.  Upper Layer Protocol is often used
        to refer to the next-highest protocol in a particular
        {protocol stack}.
     
        (1999-02-17)