Hello, On Fri, Jan 24, 2014 at 3:02 AM, John Syn <john3...@gmail.com> wrote: > On 1/23/14, 2:45 AM, "Dmitry Eremin-Solenikov" <dbarysh...@gmail.com> wrote: >>On Thu, Jan 23, 2014 at 8:04 AM, Varka Bhadram <var...@cdac.in> wrote: >>> Where is the CSMA-CA implementation ? Is it there in H/w (IEEE-802.15.4 >>> radio example:cc2520) itself or is it there at the mac802154 in linux ? >> >>CSMA/CA has so strict timing requirements (logical, you check that the >>channel is >>free and then you immediately should start to transfer), that it's >>just unpractical >>and unrealistic to implement any CSMA/CA / CCA handling in the kernel >>itself. >> >>Either your hardware should implement that for you, or you are out of luck >>and just hope that the channel is clear. > Any thoughts about implementing this with Xenomai? On BeagleBoneBlack, we > see worse case interrupt latency of 40uS to 50uS which should be > sufficient for this requirement.
Back at the times when the stack was developed at Siemens, usage of Xenomai was considered as one of the options to get ACK and CSMA/CA timings. However we never got to actually using that. One of the main reasons was the lack of the time. There were always more important features missing. Partially it was due to our radios (at86rf231 or custom dongles with Freescale radio and uC) at least theoretically supporting AutoACK and CSMA/CA. Basically, if you want to, you can try implementing that, provided that you do not push Xenomai dependencies into the 802.15.4 core. -- With best wishes Dmitry ------------------------------------------------------------------------------ CenturyLink Cloud: The Leader in Enterprise Cloud Services. Learn Why More Businesses Are Choosing CenturyLink Cloud For Critical Workloads, Development Environments & Everything In Between. Get a Quote or Start a Free Trial Today. http://pubads.g.doubleclick.net/gampad/clk?id=119420431&iu=/4140/ostg.clktrk _______________________________________________ Linux-zigbee-devel mailing list Linux-zigbee-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-zigbee-devel
