Hello David I’m really interested to see your results and proposal for improvements.
If people are interested we could set up an hour virtual interim. We must have it 3 weeks in advance which means early June. In the meantime, yes please consider whether there are simple adjustments to the spec that could be made before we ship it. We’re very late in the process so we have to act swiftly. Many thanks! Pascal > Le 10 avr. 2020 à 00:27, David Hauweele <[email protected]> a écrit : > > Dear 6TiSCH, > > In the last few months, we performed a small scale study of the > behavior of 6TiSCH's minimal scheduling function (MSF) under stress. We > were especially interested in the dynamics of MSF's automated > adaptation to traffic load. Some of our conclusions have been > summarized in a paper that we submitted to IEEE ISCC 2020. A copy of > the evaluation section of our submission is attached to this mail. > > Among our surprising findings, we observed that > > 1) The time required for MSF to adapt to a traffic change depends on > the current number of cells allocated. To give an example, it takes > much longer to go from 0 to 10 cells than from 10 to 20 cells. We > attribute this behavior to the way MSF measures cell occupancy by > counting the number of used and passed cells. Adaptation only occurs > when the number of passed cells reaches a maximum. However, with light > cell allocation, it takes longer to reach that maximum than with higher > cell allocation. > > 2) MSF can lead to severe over-provisioning, which can be harmful in an > environment where the resources are scarce. We noticed that releasing > cells was especially hard for MSF due to the fixed hysteresis > thresholds. Indeed, the estimated cell occupancy must drop below 25% > for cells to be released. > > We already have ideas to improve MSF's traffic adaptation mechanism, > that we plan to put under test in the coming weeks. We can also provide > you with more details if you wish. If you see interest in our evaluation > and proposals, we are eager to discuss this further with the WG. > > Best regards, > David, Bruno, Aris and Georgios > <msf-1.pdf> > _______________________________________________ > 6tisch mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/6tisch _______________________________________________ 6tisch mailing list [email protected] https://www.ietf.org/mailman/listinfo/6tisch
