A performance analysis of the Ethernet nets for applications in real-time: IEEE 802.3 and 802.3 1 Q

Ethernet technology dominates the local net market of computers. However, it was not established as a technology for industrial automation, where the requirements demand determinism with a performance of real time. Many solutions have been proposed to solve the problem of the no determinism, which are based mainly on the TDMA (time division multiple access), token pass and master-slave. It is in this context that this paper carried through measures of performance on communication nets that use the standard IEEE 802.3, observing the behavior of these nets when submitted to different scenes of overload. For this, variations were adopted in the test environment, which will be based on Shared Ethernet (Hub), Switch Ethernet and Switch Ethernet with priority (IEEE 802.1Q). This way, being capable to indicate which devices analyzed among the performance tests demonstrated a more appropriate behavior to support the applications with the time requirements of real time.