Date: Wed, 20 Aug 2014 16:55:07 -0700 From: Adrian Chadd <adrian@freebsd.org> To: PseudoCylon <moonlightakkiy@yahoo.ca> Cc: Kevin Lo <kevlo@freebsd.org>, "freebsd-wireless@freebsd.org" <freebsd-wireless@freebsd.org> Subject: Re: FreeBSD current RT3071 can't connect to 5G network Message-ID: <CAJ-Vmon1Qsx4AP50WGs%2BMigbT38=wMHt0kvb6dbWEdhP-aXo%2BA@mail.gmail.com> In-Reply-To: <CAFZ_MY%2Bv978t5Kqr4ds8AiD=Dh1f=2KdbxB2WJY9pmyO8vVqmQ@mail.gmail.com> References: <CAFZ_MY%2BTZCUCuMUT0X0xwVWrYbyQ4trF21ac1JPkiGxGoUJPeQ@mail.gmail.com> <CAJ-Vmo=US1q%2BGYsQJegDKsFaWMdzS17y-GhDLz3LXpfRgdA4vw@mail.gmail.com> <CAFZ_MY%2Bv978t5Kqr4ds8AiD=Dh1f=2KdbxB2WJY9pmyO8vVqmQ@mail.gmail.com>
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On 20 August 2014 16:33, PseudoCylon <moonlightakkiy@yahoo.ca> wrote: > On Wed, Aug 20, 2014 at 1:29 PM, Adrian Chadd <adrian@freebsd.org> wrote: >> Are you seeing RX CRC errors for all rates? CCK? OFDM? HT? At all distances? > > CCK not sure, OFDM and HT yes. And at wide range of distances. (Tx > rates usually hit mcs 12 to 14 with 2s ht20 ap) > >> >> There's a handful of things we can look at to see what's causing it >> once some more digging is done. >> >> (Eg, HT? could be guard interval. OFDM has similar issues, there's >> typically ways to configure how much time between each symbol is left >> before transmitting the next one. It may not be doing CTS-to-self, or >> it may not be advertising the right thing via NAV, or it may be >> ignoring CCK, or the receive gain tables are all messed up, etc.) > > I have looked into stuff I was able to dig out from other src codes, > ie protection, ifs, nav, bk slot. (Because I do not have datasheet, > every thing is based on my guesses.) One thing I could not figure out > is if on-chip memory is properly allocated for rx pkt. (It seems > memory can be allocated for different things, ie beacon, enc keys). > So CRC errors are pretty normal with wifi. Even a tiny bit of interference generates CRC errors. That's why there's an ACK and retry mechanism. :P If you're hitting MCS 12 then you're doing pretty well. A-MPDU will see lots of CRC errors just because of how long the transmissions are and how easily corrupted things can get. That's again why there's a quick retry mechanism for things. What %age errors are you seeing? -a
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