[MLB-WIRELESS] FW: Linksys RTS/CTS

[Dan Flett]

Interesting explanation of RTS/CTS...

-----Original Message-----
From: talk-bounces at seattlewireless.net
[mailto:talk-bounces at seattlewireless.net] On Behalf Of Casey Halverson
Sent: Saturday, 30 April 2005 8:56
To: SeattleWireless Talk List
Subject: RE: Linksys RTS/CTS

Nearly all serial and radio communications make use of some sort of flow
control, like CTS/RTS .. Its not really ham radio per se.  But you will
find that the 802.11 MAC is very close to AX.25.

RTS Threshold is what you want.  

RTS Threshold explanation:

Frames at and over this threshold size cause the AP to reserve the
medium with RTS.  The AP will also send a CTS to any RTS sent.  The idea
is that a hidden third party will at least hear the AP send an "RTS" or
the client send an "CTS", so it will not cause a collision.   

Any frames under this size will be just transmitted without reserving
the medium.  This would just add severe overhead, as your flow control
would far exceed the size of the packet transmitted.  The 802.11 MAC has
enough overhead as it is.

Setting a too low of RTS/CTS value will reduce your packet/sec rate,
which will ultimately cause latency. Since many interactive applications
use small packet sizes, it will hit you in the worst way.

You will also see fragmentation threshold, it works the same way, except
it just fragments the packet past a specified size.  You probably don't
want to set this too low.  If you transmit a lot of large frames in a
high noise/error rate environment, it can reduce retransmit overhead.  

The important thing to note is, both above add lots of overhead and
should be used with care.  

You may want to send beacons more infrequently on long links.  Since
stations and the AP really cant agree on what time it is, a frame could
arrive when a beacon is being sent, vice versa.  Its best to keep the
amount of chatter to a minimum.





________________________________

	From: talk-bounces at seattlewireless.net
[mailto:talk-bounces at seattlewireless.net] On Behalf Of Franklin S Werren
	Sent: Friday, April 29, 2005 1:02 PM
	To: SeattleWireless Talk List
	Subject: Linksys RTS/CTS
	
	
	OK .... I had to rattle the cobwebs on packet radio
	I know about RTS/CTS .... Where is it in a WAP54g Linksys
	with the Svensoft software....????
	Is it labled differently ????
	http://www.bagpipes.net/files/linksys-settings.jpg
	 
	This discussion is getting more and more like a Ham packet radio
discussion .....
	 
	N2JYG    
	
	Franklin S. Werren  www.bagpipes.net   www.chautauqualake.net
	 
	My 2 cents: Never get caught between an ISP and a telco in a
pissing match!!
	                   The customer looses every time!!!
	
_______________________________________________
Talk mailing list
Talk at seattlewireless.net
http://seattlewireless.net/mailman/listinfo/talk

To unsubscribe: send mail to majordomo at wireless.org.au
with "unsubscribe melbwireless" in the body of the message