Precision of ethernet measurements based on software tools

The use of Ethernet based solutions in automation applications raises the question of test tools. Free tools like Wireshark, formerly known as Ethereal, are available and offer decoding of real-time Ethernet like PROFINET IO. But is such a software based tool able to measure the required real-time constraints? What are the limits of such software based measurements? This report gives an overview of possible measurement setups and a choice of measured benchmarks.