A method for transmitting a message packet from a network device having multiple transmit queues at a precise time flushes all packets previously enqueued in a selected transmit queue and places the message packet in the selected queue. All other transmit queues are also flushed prior to transmitting the message packet to eliminate timing uncertainty due transmission of enqueued packets prior to the transmission of the message packet.
A method and apparatus for providing security to factory automation devices in a switched Ethernet network. Traffic between factory automation devices and an Ethernet switch is limited to packets including approved TCP/UDP port numbers and to selected data rates.
