The use of Ethernet switched networks usually involves best effort service. A recent effort by the IEEE 802.1/3 TSN group has sought to standardize the Ethernet data-link protocol such that it operates on a deterministic service in addition to the best effort service targeting Operational Technology applications, e.g., industrial control systems. This paper investigates the Cyclic Queueing and Forwarding (CQF) and Paternoster scheduling protocols in a typical industrial control loop with varying propagation delays emulating large scale networks. Our main findings for CQF and Paternoster are that CQF has an advantage towards real-time streams with hard-deadlines whilst Paternoster is for streams with more relaxed deadlines but can operate without time synchronization.
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