Which protocol does Ethernet TCP/IP use to suit automation and control networking?

The use of the Common Industrial Protocol (CIP) in Ethernet TCP/IP for automation and control networking is significant because it was designed specifically to support industrial automation applications. CIP provides a framework for communication among devices and systems in a factory, focusing on interoperability between different products and manufacturers.

CIP operates over several network types, including Ethernet, and it encompasses services for device configuration, control, and data exchange. This makes it particularly suitable for real-time data transfer and control scenarios found in automation environments. By using CIP, devices can communicate in a standardized way, ensuring that data such as status information, diagnostics, and control commands are transmitted efficiently and reliably.

In contrast, the other protocols mentioned are not tailored specifically for industrial automation. For example, HTTP is primarily used for transferring web pages, FTP is focused on file transfers, and SMTP is used for email transmission. While these protocols serve important functions in IT networking, they do not provide the necessary capabilities for high-performance, real-time control critical in industrial environments. Thus, CIP stands out as the appropriate choice for Ethernet TCP/IP in automation and control networking.