This document discusses the development and testing of safety network protocols for applications in automotive, industrial automation, and other fields. It outlines several issues with network communication such as access denial, repetition, loss, corruption, and timeouts. It then describes techniques for addressing these issues, including the use of VLANs for access control, CRC and hash functions for error detection, supervision packets for connection monitoring, and timestamps for timeout detection. Finally, it discusses tools for testing protocols, such as Wireshark, Scapy, TTCN-3, PTP, and PRP, which provides redundancy against network failures.