On Sat, Jan 28, 2012 at 11:58 AM, Marek Lindner <lindner_marek@xxxxxxxx> wrote: > On Sunday, January 29, 2012 03:17:32 Daniel Halperin wrote: >> Adaptive RTS/CTS is important to control for interference---RTS/CTS is >> there so that other Wi-Fi devices know not to interfere with your >> flow. It may well be the case that this is not a major problem in >> whatever your scenario you're working, Marek, but it makes a big >> difference in a many bad corner cases. > > I am very well aware of what RTS/CTS is for and I am not against using it. > However, having the rate algorithm overriding the user setting for a specific > rate is extremely hard to grasp or debug. > To give you an understanding where I am coming from: In our networks we > experienced extremely variable throughput ranging from 30Mbit/s (single > stream) to 0.2 Mbit/s in the next second. As you can imagine we were trying to > figure out what was going on. After spending some time and losing hair I > noticed that the RTS/CTS implementation of our driver (ath9k) is buggy. Every > once in a while the nodes would "battle" each other with RTS/CTS packets. > Strange enough for us, sometimes no RTS packets were sent and sometimes they > would battle. All attempts to disable RTS/CTS for the mere sake of testing(!) > was impossible. First I thought ath9k did not properly implement the "iw rts" > setting but that wasn't the case. After losing more hair I realized that > minstrel_ht, a rate control algorithm(!), was overriding my rts settings but > not always(!). The only way to make RTS shut up was to apply the posted patch. Can you explain what the low-level behavior of an RTS/CTS "battle" is? Abstractly, the behavior you're describing sounds like a buggy driver that doesn't obey overheard RTS or CTS packets. Dan -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
