Date: Mon, 8 Jul 2002 19:55:21 -0400 From: David Gilbert <dgilbert@velocet.ca> To: John Kozubik <john@kozubik.com> Cc: "M. Warner Losh" <imp@village.org>, freebsd-hackers@FreeBSD.ORG Subject: [hackers] Re: multi-link 802.11b through netgraph yields poor performance. Message-ID: <15658.9833.148556.28650@canoe.velocet.net> In-Reply-To: <Pine.BSF.4.21.0207071629240.40375-100000@www> References: <20020707.121836.61267901.imp@village.org> <Pine.BSF.4.21.0207071629240.40375-100000@www>
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>>>>> "John" == John Kozubik <john@kozubik.com> writes: >> Also, before blaming netgraph, which may well be to blame, could it >> be that you have interference from some other source that's making >> things bad? The exactly every other packet being dropped does seem >> to be a big clue. John> I have ruled out interference as a contributor to these results. John> So, the point made earlier in this thread that the behavior I John> produced looked like the behavior of a ng_one2many setup with John> 50% of the link not working seems to be correct. However, John> because the first test I mentioned above (two wireless nets John> operating simultaneously across two systems without netgraph) John> succeeded, I am not simply dealing with a bad card or a down John> link. Naw (I know this one). It's the same reason that netgraph bridging doesn't work on wireless cards. The firmware on your card prevents you from sending a mac address that is not your own as the source mac address. This is an attempt by the wireless chipset cabal to prevent you from building your own access point. (You can't be a bridge if you can't transmit arbitrary mac addresses) For most cards, there's no workaround. For a few cards, it's rhumored that you can hack the firmware (DLink is one I've heard mentioned). If you hacked netgraph to set the source mac address to the source mac address of each card, everything would likely work. On second thought, tho, you might need to hack arp (et. al.) to do the right thing (or only have arp repsonses go out the primary interface). Dave. -- ============================================================================ |David Gilbert, Velocet Communications. | Two things can only be | |Mail: dgilbert@velocet.net | equal if and only if they | |http://daveg.ca | are precisely opposite. | =========================================================GLO================ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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