[CUWiN-Dev] [Fwd: [CWN-Summit] 802.11b long-distance ACK timeout]

[John Atkinson]

Bob,

Atheros chipsets allow us edit the acktimeout and ctstimeout parameters to
accomodate long-distance links.  To change it on a CuWin router (NetBSD) you
would do something like:

# sysctl -w hw.ath0.acktimeout=203
# sysctl -w hw.ath0.ctstimeout=203

from a console.

These commands change the timeouts from their default of 48, on this Atheros
chip (D-Link DWLG520), to 203.

There is a whitepaper with more information published on the Wireless Ghana
website:
http://www.wirelessghana.com/node/7

The downside to increasing these timeouts is that clients of an access point
that are in closer proximity will notice a decrease in speed if/when packets
actually are dropped.

What specific equipment setups are you working with, wifi model numbers and
OS's?  I don't know if it is possible to do this on an off-the-shelf router;
I haven't tried, and they aren't really designed by the manufacturers with
people like us in mind.  Check out all of the options on any of the
interfaces you have into it, like a web configuration page.  Maybe you could
set up the client with a point to point link using CuWin.

-- 
Regards,

John Atkinson
Director - Wireless Ghana


Our wireless efforts in rural Appalachia now have a case where a user
> is far enough away from our access point, that the ACK timeout
> problem is preventing connection.   We have some ideas on how to
> solve this, but we would also like to hear from the collected wisdom
> of this group as to how they have solved it.    We are using a D-Link
> access point; does anyone know how to change the ACK setting on this?
> What other access points have you used successfully which allow ACK
> to be changed?   How can the ACK be changed in a PC endpoint?
>
> Thanks!
>
>            Bob
>
> --
> Robert S. Dixon, Ph D, PE
> Chief Research Engineer
> Ohio Academic Resources Network (OARNet)
> and
> Ohio State University, Office of the CIO
>
> Office Telephone: 614-292-1638
> Fax:              614-292-7081
> _______________________________________________
> CWN-Summit mailing list
> CWN-Summit at lists.cuwireless.net
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>
>
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