Message fragmentation of event-triggered traffic in TTEthernet systems using the Timely Block method

TTEthernet is a communication protocol of real-time Ethernet that expands standard Ethernet with deterministic real-time services. TTEthernet was designed to support mixed-criticality applications coexisting in a single network infrastructure. With the Timely Block method, a TTEthernet switch does not relay an event-triggered message (rate-constrained and best-effort traffic) if it has found that the transmission of the event-triggered message will not have been finished before the forthcoming time-triggered message has to be relayed according to a predefined time-triggered communication schedule. So, the even-triggered message has to be delayed and wait in the queue buffer of the TTEthernet switch, so that the forthcoming time-triggered message can be timely relayed. During the waiting time of the even-triggered message before transmitting the forthcoming time-triggered message, the communication channel is idle for message transmission. This time interval is called the Timely Blocking Time. In this paper, an approach called Message Fragmentation was proposed to fragment event-triggered messages in TTEthernet systems using the Timely Blocking method in order to utilize the communication channels during Timely Blocking Times. The throughput performance of the event-triggered traffic in the TTEthernet systems with and without the Message Fragmentation approach was observed with respect to various payload data sizes by means of simulation. The simulation results showed that the Message Fragmentation approach obtained the throughput enhancement of the event-triggered traffic in the conventional TTEthernet systems, especially the event-triggered traffic with large payload data sizes.