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Building a reliable communication network is a challenging task using the standard Ethernet as the medium for control and data acquisition networks. Such sensor-actuator networks could be distributed across multiple locations across a building. Packet retransmissions and losses could be critical when Ethernet is used for closed-loop controls and measurements. There could be multiple design challenges to build such networks such as total-traffic, compact node design, bandwidth limitations, packet retransmissions, delays, drops etc. In this paper, we report how we implemented a reliable http-based automation network of large interconnected microcontroller-based nodes with a careful design of hardware, firmware components and a new application-layer faulty-node-filter-algorithm. It analysed some of the top causes of poor network performance within such control networks using a popular network protocol-analyser "Wireshark". Though Ethernet seemed the most future promising, it has the single drawback of nondeterministic packet transfers. Additional research is carried out to prove that IEEE 802.3 standard Ethernet could be used in applications like our slow-cryogenics-control systems of linear Accelerators to build an error-free, near deterministic control-application. This approach allowed the continued use of conventional Ethernet networking components. even for the control networks and the same communication medium. The tested system is distributed within a private LAN of more than 50 embedded servers each of which is built out of on-chip TCP/IP stacks implemented on ARM processors as nodes, for a successfully implemented Cryogenic control network of Superconducting linear Accelerator at Inter University Accelerator Centre, New Delhi, India. [ABSTRACT FROM AUTHOR]