Hi Tengei, the problem you are rising is that you would like to see a number of cells to add/delete when comparing required and deleted cells.
The ancestor of SF0, namely OTF, used to specify the following sentence: The number of soft cells to be scheduled/deleted for bundle resizing is out of the scope of this document and implementation-dependant. In fact, we wanted to let that choice being implementation specific. What you are proposing (the exact number of cells to add or delete) was already implemented in the 6tisch simulator, and it is in fact something that has already been used and tested in the following papers: Palattella et al., On-the-Fly Bandwidth Reservation for 6TiSCH Wireless Industrial Networks, IEEE Sensors Journal, 2015 Muraoka et al., Simple Distributed Scheduling with Collision Detection in TSCH Networks, IEEE Sensors Journal, 2016 But, as already said, this is just a way you can allocate cells. I guess we don't want to restrict that setting to a particular algorithm choice. Hope this helps. Nicola 2016-11-02 14:59 GMT+01:00 Tengfei Chang <tengfei.ch...@gmail.com>: > Hi All, > > I am reading the SF0-02 version which is just released few days ago. > > In the SF0 Allocation Policy section, the policy said > > 1. If REQUIREDCELLS<(SCHEDULEDCELLS-SF0THRESH), delete one or more > cells. > 2. If (SCHEDULEDCELLS-SF0THRESH)<=REQUIREDCELLS<=SCHEDULEDCELLS, do > nothing. > 3. If SCHEDULEDCELLS<=REQUIREDCELLS, add one or more cells. > > > > Personally thinking, add/delete one cells may call the sixtop many times > which is not efficiency, add/delete more cells is not clear to the > implementer. > I guess there is a decision to say when to add one cell and when to add > more cells. But I didn't find it in SF0 draft. > Is there any reason why we doesn't say specific number of cells? > > If no, I think we can add/remove the number of cells to make sure the > scheduled cells equals to the required cells plus half of SF0THRESH, which > will help stabilize a little bit of the SF0, in case the sixtop is calling > too often. > > Which means: if SCHEDULEDCELLS<=REQUIREDCELLS: > > 1. when there is no cell in the schedule add one cell > 2. when there is at least one cell in schedule, add > REQUIREDCELLS-SCHEDULEDCELLS+(SF0THRESH+1)/2 number of cells > > if REQUIREDCELLS<(SCHEDULEDCELLS-SF0THRESH)) > > 1. When required cells equals 0, remove all cells but keep one in schedule > 2. when required cells is greater than 0, remove SCHEDULEDCELLS- > REQUIREDCELLS-(SF0THRESH+1)/2 > > Does this make sense? > > Tengfei > > -- > Chang Tengfei, > Pre-Postdoctoral Research Engineer, Inria > > _______________________________________________ > 6tisch mailing list > 6tisch@ietf.org > https://www.ietf.org/mailman/listinfo/6tisch > >
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