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[70.114.247.242]) by smtp.googlemail.com with ESMTPSA id x15-20020a056830408f00b006b9848f8aa7sm525268ott.45.2023.11.02.08.17.48 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 02 Nov 2023 08:17:49 -0700 (PDT) Message-ID: <424127a9-af47-4a15-91f1-ff97e7ceacc8@gmail.com> Date: Thu, 2 Nov 2023 10:17:47 -0500 Precedence: bulk X-Mailing-List: iwd@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/4] Packet/beacon loss roaming improvements Content-Language: en-US To: James Prestwood , iwd@lists.linux.dev References: <20231030134837.452957-1-prestwoj@gmail.com> <0cf695c9-7abc-40e9-a6fa-fdd10589839b@gmail.com> <70935a8f-1f38-4e9e-8d77-40179c2b31f3@gmail.com> <68d50637-4b8d-4690-bfac-e379e1044492@gmail.com> <27703a4f-a071-4ff7-afbc-8dda1c5b0b27@gmail.com> <16ab09cc-0ba9-4c01-9f92-47e05aac2160@gmail.com> From: Denis Kenzior In-Reply-To: <16ab09cc-0ba9-4c01-9f92-47e05aac2160@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi James, > > In the behavior I witnessed which was actually quite reproducible at the time, > and yes roaming on beacon loss definitely helped. It avoided an inevitable > disconnect. > Okay, then lets put this in with a 1-2 delay to let the kernel disconnect if it is going to. >> >>> >>> I'm not sure how, but being able to detect if the AP responded to >>> nullfunc/probes prior to the kernel blowing away the connection would be >>> great. (like send our own nullfunc frames or something, not really sure...) >> >> Yes, the current implementation of this event in the kernel is pretty useless. >> What we really need is an additional threshold that generates an event out to >> userspace _before_ the kernel starts taking potentially irreversible actions. >> Something like a pre-beacon-loss event that gets generated when 2-3 beacons >> are lost in a row. > > Best would be an event like "Disconnection Imminent" (after the 2 nullfuncs It is too late by that point. > failed) so userspace could start a roam. Like you mentioned even if we knew a > few beacons were lost, scanning is probably going to ruin any chance of recovery. > > In theory only 5: > known_freq_set = known_networks_get_recent_frequencies(5); > No, that picks the top 5 most recently used networks. The known frequencies for each of the top 5 are added to the quick scan. This works okay most of the time, but we do not rotate out known frequencies, so if you have a network with lots of APs spread out over the spectrum, it might end up scanning quite a bit. Regards, -Denis