Date: Tue, 23 Nov 2010 10:43:57 -0600 From: Larry Vaden <vaden@texoma.net> To: Adrian Chadd <adrian@freebsd.org> Cc: freebsd-mips@freebsd.org Subject: Re: does anyone have a recommendation for a solid FreeBSD-based 802.11b/g/n AP package for MIPS-based APs and CPEs? Message-ID: <AANLkTi=NFHHOq2cXXQ8w8PawNSksiqpaW5WSXimkcpQj@mail.gmail.com> In-Reply-To: <AANLkTim8-4Guwh7rgn9cGqffn29q7k8eC_Kc2X2o32ub@mail.gmail.com> References: <AANLkTik_vvgQfhh_K-OecR-CE8nBWu=A3Kuvt8BYdXSZ@mail.gmail.com> <AANLkTikTRMMZHFjFOo-tWGgJ1=EVu0e2pMR8ScVVNfs9@mail.gmail.com> <AANLkTi=WhMTFK=eLaZb2DNG0NE0HmUBiQqfw1_6E29q1@mail.gmail.com> <AANLkTi==En8kS6H_7sxTGFMrEO3KLAbQwgMWsAwb9A2w@mail.gmail.com> <AANLkTinUKjgtM9iqsjdvO_achUMRPPCZGgcnXBKxw04e@mail.gmail.com> <AANLkTim8-4Guwh7rgn9cGqffn29q7k8eC_Kc2X2o32ub@mail.gmail.com>
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On Tue, Nov 23, 2010 at 9:30 AM, Adrian Chadd <adrian@freebsd.org> wrote: > > I've no idea. I haven't at all looked at WDS. > > As Sam likely pointed out, stuck beacons can include: > > * because the RF environment is somehow hilariously bad, congested or > dirty (seen this); > * because the code needing to setup the beacon frames, flush it to RAM > before the TBTT (and related) timers fire just doesn't get a chance to > run (seen this); > * because your backend PCI bus/CPU/FSB bus/etc is busy, and thus the > beacon frame doesn't go out in time (haven't seen this); > * because the chip is being fondled in the wrong way somehow and it's > locking up something (definitely seen this.) > > It's just a shame that people focus on "stuck beacon!" rather than > trying to figure out what other events are occuring at the same time. > :-) > > To track down stuck beacons at my wireless contract, I ended up doing > a -lot- of instrumentation to try and figure out what was going on > when stuck beacons occured. For example, stuck beacons were occuring > in the deep past because the initial noise floor calibrations were > being done every 1/10th of a second during a periodic calibration > (every 20 minutes), rather than every few seconds, and this tended to > upset the radio. > > Adrian Adrian, Thanks for your reply. I agree with you and we are trying to understand the underlying causes and what can be done. I also agree that changing the intervals can help; we found that a beacon interval of 200-250 msec resulted in better latency for subscribers, but that higher beacon intervals seemed to be unstable (CPEs would reassociate every few seconds). This was on Ubiquiti gear. AFAIK, the beacon interval on Mikrotik's RouterOS is fixed at 100 msec (read: not under operator control), and the recalibration interval is 00:01:00, also not under operator control. In these cases, I refer to WinBox, not the CLI, which I haven't checked. kind regards/ldv
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