Re: Trouble with long distance link ~40km

On 24-Jun-2002 [email protected] wrote:
> Hi!
> 
> I build long distance link ~40km, at both side use freebsd 4.5 rel.
> ftp transfer very low ~ 6kb per sec but eb/no 30-32dbm(at both side), help me
> to fix this trouble or explain
> where i can read about solutions this...

Apart from the suggestions that others have given, this may be down to
MAC layer timing problems. 802.11 has specific time outs at the physical
layer that are only about 15 micro-seconds. With your 40km link, the
packets take 40e3/3e8=133us to travel across the link. This will
cause lots of MAC timeouts (e.g. when sending a packet an ACK is required
in a few micro-seonds, I cannot remember the details, but it is under 20us).
These will cause lots of re-transmits.

Try reducing the packet size and using CTS/RTS handshaking.

Duncan

> Big thank's
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>  oleg                          mailto:[email protected]
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Duncan Barclay  | God smiles upon the little children,
[email protected]   | the alcoholics, and the permanently stoned.
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