From a protocol stack perspective and with a view to backward compatibility, the extension of today’s Ethernetbased field-level networks into the wireless range seems to be quite straightforward for the solutions using plain Ethernet and maybe TCP/UDP encapsulation of fieldbus application layers (see also Fig. 4), such as Ethernet/IP with the CIP or MODBUS. In these cases, Ethernet could be replaced by wireless technology providing an IP channel. The availability of an IP layer is not a matter, of course, in the various wireless technologies currently considered for automation networksa