This International Standard is applicable to high-availability automation networks based on the ISO/IEC 8802-3 (Ethernet) technology. This International Standard specifies ? a classification scheme for network characteristics (see Annex A); ? a methodology for estimating network availability (see Annex B); ? a set of communication protocols that realize high availability automation networks via the use of redundancy and that can be used in a variety of applications (see Clauses 5@ 6@ 7@ 8).