📝 SummarXiv

Abstract

For packet-switched networks, when the packetization effect is overlooked, network calculus analysis can produce faulty results. To exemplify, network calculus analysis is applied in this paper to two basic systems that are fundamental or default settings in Time-Sensitive Networking (TSN) and Deterministic Networking (DetNet). Through counterexamples, it is revealed that for the two fundamental settings, some widely adopted, network calculus-based service characterization results, known as service curves, which ignore packetization, are faulty. In addition, for performance bounds derived from the faulty service curves, it is shown that the validity of the bounds can be arguable. In particular, the output bound, backlog bound and concatenation service curve results are shown to be also faulty: counterexamples can be constructed. By factoring the packetization effect directly into the service models, corrected service curves and performance bounds are derived for the two basic systems. These results remind that special care is needed when applying network calculus analysis to packet-switched networks.