Industrial plant use requires consideration of the environment in which the equipment must operate.
Plant-floor equipment must tolerate a wider range of temperature, vibration, and electrical noise than
equipment installed in dedicated information-technology areas. Since closed-loop process control may rely on an Ethernet link, economic cost of interruptions may be high and availability is therefore an
essential criterion. Industrial Ethernet networks must interoperate with both current a
nd legacy systems, and must provide predictable performance and maintainability. In addition to physical compatibility and low-level transport protocols, a practical industrial Ethernet system must also provide interoperability ofhigher levels of the OSI model. An industrial network must provide security both from intrusions from outside the plant, and from inadvertent or unauthorized use within the plant