2026-10-11T13:39:34Z https://drops.dagstuhl.de/oai

oai:drops-oai.dagstuhl.de:25612 2026-06-23T10:10:21Z ddc:004 open_access

Making Congestion Control Algorithms Insensitive to Underlying Propagation Delays Illick, Cyrus Roger, Michael Misra, Vishal Rubenstein, Dan Congestion Control Propagation Delay Underlying propagation delays, which significantly impact flow Round-Trip-Times (RTTs), fundamentally shape how congestion control algorithms (CCAs) allocate bandwidth among competing flows. Traditionally, lower RTTs were desirable, as a flow rate would decrease as RTT increased under conventional CCAs such as Reno and Cubic. More recently, algorithms like BBR reversed this behavior, favoring flows with larger RTTs. In modern heterogeneous networks, where competing flows may employ different CCAs and serve diverse application workloads, notions of fairness become ambiguous and RTT’s role further complexifies addressing an already very challenging problem. We offer a simple but initially counter-intuitive remedy to address how all CCAs can remove this inherent sensitivity to propagation delay: have all flows "emulate" the same underlying propagation delay. Unsurprisingly, this idea is often met with a lot of resistance, since it is in many ways counter to many fundamental tenets of networking and congestion control. In this paper, we try to make the case that while the idea is not a silver bullet on its own, it can greatly simplify design and predictability across existing and future congestion control protocols going forward. Schloss Dagstuhl – Leibniz-Zentrum für Informatik Cyrus Illick and Michael Roger and Vishal Misra and Dan Rubenstein 2026 Is Part Of OASIcs, Volume 139, 1st New Ideas in Networked Systems (NINeS 2026) InProceedings Text doc-type:ResearchArticle publishedVersion application/pdf doi:10.4230/OASIcs.NINeS.2026.27 urn:nbn:de:0030-drops-256122 https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.NINeS.2026.27 eng https://creativecommons.org/licenses/by/4.0/legalcode