Re: one side show: associated and second side show: no carrier

Daniel Dvoøák wrote:
> Hello all,
>  
> first of all I would like to thank Sam L. and others how helped with
> 80211ieee and atheros driver. Your work in last months is great !
>  
> With new ath_hal in source in RELENG_6 I decided to buy 2 new Wistron WNC
> CM10 with MAC chip AR5414A to connect 2 nodes with distance 3,5 km.
>  
> My problem is associated or not.
>  
> One side where is hostap show this:
>  
> # ifconfig ath1 list sta
> ADDR               AID CHAN RATE RSSI IDLE  TXSEQ  RXSEQ CAPS ERP
> 00:0b:6b:XX:YY:ZZ    1  108   6M   33  180   1200     16 E      0 WME
> 
> RSSI=33, okay 33-95 = -62 dBm
>  
> A datasheet for CM10 said for receive sensitivity:
> -85dBm_at_6Mbps
> -67dBm_at_54Mbps
>  
> So theoretically the client should work with 6-54 Mbps/s without any
> difference, because the RF signal is enough to associate even at 54Mbps/s.
>  
> Now go to client side, and what it show:
>  
> ifconfig -v ath0
>  
> ath0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>         inet6 fe80::20b:6bff:fe2a:c78e%ath0 prefixlen 64 scopeid 0x2
>         inet 10.40.64.18 netmask 0xfffffffc broadcast 10.40.64.19
>         ether 00:0b:6b:XX:YY:ZZ
>         media: IEEE 802.11 Wireless Ethernet OFDM/6Mbps mode 11a
>         status: no carrier
>         ssid PtP channel 108 (5540) bssid 00:00:00:00:00:00
>         authmode OPEN privacy OFF deftxkey UNDEF powersavemode OFF
>         powersavesleep 100 txpowmax 37 txpower 63 rtsthreshold 2346
>         mcastrate 1 fragthreshold 2346 pureg protmode OFF wme burst
>         roaming AUTO bintval 100
>         AC_BE cwmin  4 cwmax 10 aifs  3 txopLimit   0 -acm ack
>               cwmin  4 cwmax 10 aifs  3 txopLimit   0 -acm
>         AC_BK cwmin  4 cwmax 10 aifs  7 txopLimit   0 -acm ack
>               cwmin  4 cwmax 10 aifs  7 txopLimit   0 -acm
>         AC_VI cwmin  3 cwmax  4 aifs  2 txopLimit  94 -acm ack
>               cwmin  3 cwmax  4 aifs  2 txopLimit  94 -acm
>         AC_VO cwmin  2 cwmax  3 aifs  2 txopLimit  47 -acm ack
>               cwmin  2 cwmax  3 aifs  2 txopLimit  47 -acm
> 
> ifconfig ath0 list ap
>  
> SSID            BSSID              CHAN RATE  S:N   INT CAPS
> PtP          00:0b:6b:XX:YY:ZZ  108   54M 24:0   100 E    WME
> 
> It said "no carrier".
>  
> RF signal on client side is lower, okay but 24-95 is -71dBm so it is enough
> signal strength to associate to AP at the minimum 6 Mbps/s.
>  
> But it does not work. Any operation at both side like ifconfig ath0 down and
> up do not help me.
>  
> How can hostap side say: "yes I see my client, it is accossiated to me with
> this mac", and client say: "yes I see my ap, but I could not associate to
> ap, even if I should associate to ap" ???
>  
> Any help is very appreciated.
>  
> P.S.: ath_hal, ath driver and ath sample rate is compiled to my custom
> kernel.

<<attachments deleted>>

You need to search for references on long distance links; 
google(wireless ack timeout) found a few reasonable ones.  The athctrl 
script is a faithful port of the original linux program but it's 
horrible flawed in calculating effective settings.  If you look at the 
stats you'll see lots of dup'd frames which indicates you're not getting 
an ack in time before the station retransmits.  Hence no association. 
Sniffing from a 3rd station would also show this.

If you're doing long distance p2p configs you should use adhoc demo 
mode; I added it explicitly for this application.  Then tune your IFS 
parameters to reflect the propagation delay.  Past that there are many 
things you can do to improve performance but I'll leave that to others 
to explain.

	Sam