2026-07-22T04:29:22Z https://drops.dagstuhl.de/oai

oai:drops-oai.dagstuhl.de:23596 2025-10-27T10:21:54Z ddc:004 open_access

Per-Flow Performance Guarantees in Networked Systems with Complex Feedback Structures Hamscher, Anja Wildberger, Lukas Schmitt, Jens Real-Time Networks Network Calculus Feedback Control Many modern networked real-time systems encompass complex feedback structures and require stringent timing guarantees, especially bounds on the network delay. Network Calculus (NC) is a versatile methodology to compute such performance guarantees per individual flow; in particular, some fundamental results on how to deal with feedback exist. Yet, these are restricted to simple feedback structures and are mostly constrained to an analysis at the aggregate level (not per flow). In our work, we analyze more complex feedback structures than previously investigated by reducing them to canonical structures. We transform these closed-loop systems (with feedback) into open-loop systems (without feedback) and, subsequently, perform a per-flow analysis exploiting very recent NC results on per-flow performance guarantees. In a numerical experiment, we compare our new method to the current state-of-the-art which only allows for an aggregate FIFO analysis. We also compute how feedback constraints need to be allocated to ensure that a feedback system provides the same service as the system without feedback, in a sense providing for an optimal control. Furthermore, we compare different allocation strategies under a fixed budget for the feedback constraints. Schloss Dagstuhl – Leibniz-Zentrum für Informatik Anja Hamscher and Lukas Wildberger and Jens Schmitt 2025 Is Part Of LIPIcs, Volume 335, 37th Euromicro Conference on Real-Time Systems (ECRTS 2025) InProceedings Text doc-type:ResearchArticle publishedVersion application/pdf doi:10.4230/LIPIcs.ECRTS.2025.18 urn:nbn:de:0030-drops-235961 https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2025.18 eng https://creativecommons.org/licenses/by/4.0/legalcode