On Tuesday, August 24, 2010 11:26:23 am Chris Ball wrote: > Hi Reuben, > > > Consider the benefits of using open source software versus our > > closed source firmware and partnering with communities like > > Freifunk whose network is ~ 800 node, guifi.net is almost 10k > > nodes in Barcelona, Athens Wireless is 5k nodes. > > The fact that a custom mesh algorithm would have to run on the CPU -- > prohibiting any kind of idle-suspend -- makes it a non-starter for an > XO deployment in my eyes. Did you have any thoughts on this?
We (MontevideoLibre, a free wireless community network) have been using OLSR for a while now. And though the topology in a typical OLPC scenario is very different, we've talked about assembling an image running OLSRd for a while. Anyway, I dont have time for a full response to this thread right now, but I had a conversation with smithbone and silbe a while back that may be illustrative of the worse-case scenario in terms of power consumption: <aa> silbe: I think a working PoC could gather a lot interest from deployments... <silbe> aa: one thing to consider is the power draw. with libertas_tf, the host CPU needs to be powered on. <aa> yes <aa> silbe: do you have an idea of what that means in actual numbers? <aa> perhaps smithbone has a guesstimate <silbe> aa: counter-question: are you thinking of running the protocol while the XO is "powered off" (screen off, everything in suspend with wake-on-WLAN) or just during regular operation? <silbe> for the latter case, it might not make much of a difference, especially if "automatic power management" (automatic suspend) is disabled. <smithbone> Running the system is going to cost you in the 5W range. <silbe> in the "powered off" case it's going to make a huge difference. I don't think it'll be able to run for more than 3h while there's any traffic. <aa> silbe: one of the things I want to find out is the convergence time of the different options <silbe> aa: i.e. the time until the network/mesh is stable? <aa> yes <silbe> aa: if you were in europe, you might try getting funding from the EU for that ;) <aa> silbe: also, BATMAN has a layer 2 kernel module, maybe we could make it aware of the PM state? <silbe> they seem to pay some pretty sums for mesh research * aa migrates to Europe <aa> :P <silbe> aa: it should just integrate into the kernel PM QoS framework I cuppose, see Documentation/power/pm_qos_interface.txt <aa> silbe: will do <silbe> aa: oh, and some recent mail from me has a link to nice slides explaining the PM QoS framework <aa> silbe, smithbone: do you guys know if wol would work with libertas_tf? <aa> silbe: to sugar-devel? <silbe> aa: no idea, sorry. <silbe> aa: I think to de...@l.l.o <aa> silbe: found it, thanks! <smithbone> aa: which gen? <aa> smithbone: XO-1 <smithbone> aa: on XO-1 the wakeup is generated by strobing a signal to the EC. So libertas_tf would need to support strobing that signal <aa> smithbone: thanks a lot, is this documented somewhere? <aa> too bad the firmware is closed :( <smithbone> aa: no. because none of the systems you are talking about have open documentation <aa> smithbone: I understand <smithbone> aa: But I can certainly tell someone what gpio on the wlan module to strobe and for how long. -- -Andrés
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