The Ethernet standard is a standard solution for interconnecting industrial devices despite its intrinsic drawbacks, particularly its nondeterministic medium access method. Many Ethernet-based commercial solutions available (COTS - Components Off the Shelves) on the market guarantee time performance. This means that user selection of one particular solution is a critical decision, but the choice often depends more on political strategizing with an industrial device manufacturer than on the intrinsic performance of Ethernet-based interfaces. The objective of this paper is to provide a formal behavioural analysis of each Ethernet-based solution, in order to facilitate comparison. We also consider the issue of synchronization of distributed nodes.