Segmentation of Standard Ethernet Messages in the Time-Triggered Ethernet

TT Ethernet is a communication architecture which allows the integration of the standard Ethernet traffic and real-time Ethernet traffic in the same network without invalidating the real-time properties of the real-time traffic. The TT Ethernet switch distinguishes between two classes of traffic. The standard Ethernet traffic is handled in conformance with the existing (standard) Ethernet, whereas the real-time traffic is transmitted with a constant transmission delay. In order to guarantee a constant message transmission delay, the TT Ethernet switch preempts, if necessary, the transmission of standard Ethernet messages, and retransmit the preempted Ethernet message as soon as the transmission of the real-time Ethernet message is finished. The message can be preempted several times before it is successfully transmitted, which decreases the throughput of standard Ethernet messages. In this paper we propose a segmentation mechanism for standard Ethernet frames in order to increase the throughput. The segmentation mechanism does not change the format of Ethernet frame and is transparent to higher levels of a protocol stack such as TCP/IP.