Date: Thu, 21 Jul 2005 16:47:32 +0100 From: David Malone <dwmalone@maths.tcd.ie> To: Sam Pierson <samuel.pierson@gmail.com> Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: Atheros, hardware access layer, collisions Message-ID: <200507211647.aa79456@salmon.maths.tcd.ie> In-Reply-To: Your message of "Thu, 21 Jul 2005 08:21:37 CDT." <d9204e4c050721062174d08e97@mail.gmail.com>
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> I've got two computers synchronized to send one packet each to this > machine sitting between them. This machine responds with a packet > to each that it receives (on the application level, not in the control frame > space), so if there is a collision, I don't want the middle machine to > respond and I don't want the senders to retransmit when they don't > receive an ACK control frame after they send their data packet (again, > this packet is up on the transport layer, so more control frames might > be sent). Normal operation (regular connectivity) is not needed on the > two senders, so screwing up their retransmission scheme isn't a problem. OK - you can probably achieve that by setting the retry limit to be 1, setting CWmin to be very small. However, you'll need to make sure that both machines transmissions are synchronised to better than 20us (which is no mean feat), otherwise carrier sense will foil your plan! David.
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