From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.holtmann.org (coyote.holtmann.net [212.227.132.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 209862C9D for ; Tue, 18 Jan 2022 09:31:01 +0000 (UTC) Received: from smtpclient.apple (p4fefca45.dip0.t-ipconnect.de [79.239.202.69]) by mail.holtmann.org (Postfix) with ESMTPSA id E803FCECD9; Tue, 18 Jan 2022 10:30:54 +0100 (CET) Content-Type: text/plain; charset=utf-8 Precedence: bulk X-Mailing-List: connman@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 (Mac OS X Mail 15.0 \(3693.40.0.1.81\)) Subject: Re: Network with same ssid question From: Marcel Holtmann In-Reply-To: Date: Tue, 18 Jan 2022 10:30:54 +0100 Cc: Daniel Wagner , connman@lists.linux.dev Content-Transfer-Encoding: quoted-printable Message-Id: References: <55549edc-f52b-0552-2134-d87c6dc71416@monom.org> <03304641-cc5c-4150-277e-3ac77732f9f1@monom.org> <8AF20224-E145-48EE-9484-D1527448A3CA@holtmann.org> To: Michael Nazzareno Trimarchi X-Mailer: Apple Mail (2.3693.40.0.1.81) Hi Michael, >>>>> suppose you have 3 access point with different signal strength on = a >>>>> network, the best will be connman select access point in the area >>>>=20 >>>> This selection is done by the wpa_supplicant/iwd, not by ConnMan. >>>=20 >>> the wpa_supplicatan using wpa_cli show all the network so connman >>> can create several services with the same ssid name. The logic to = what >>> service to connect is can not be done even in connman >>=20 >> actually iwd does select the best possible AP and will also roam = between them in case one AP tells iwd that a different AP is preferable = or even if it gets asks to move bands. That is all done inside iwd. It = is impossible to do sitting on top of wpa_supplicant. >>=20 > This depends on the tsf of the latest scan and how cache is managed > and on hardware too. no, it is impossible since wpa_cli only gets parts of the required = information. So you are just out of luck. Trust me on this since the = code in iwd to manage networks and roaming and band steering and so on = is actually complex. Source code is available, feel free to check for = yourself. >=20 >> Keep in mind that one physical AP broadcasting on 2.4 GHz and 5 GHz = is already two BSSIDs with the same SSID. The client (like iwd) has to = roam between the two bands. >>=20 >=20 > That was already clear but this is a different use case because you > know that both are part of the same access point. Actually you don=E2=80=99t know that. They are two independent BSSIDs as = well. >=20 >>>>>>> IIRC, ConnMan merges those together and only exposes it one = Service. >>>>>>=20 >>>>>> is_duplicated the one that merges them? I think that in scenario = when >>>>>> multiple access point >>>>>> are present we should not do it. I have seen that even iwd does = not >>>>>> show duplicated. Is that correct? >>>>=20 >>>> wpa_supplicant or iwd? I can't remember the wpa_supplicant details = here. >>>> For iwd, all these stuff is done in iwd. Not ConnMan. >>>=20 >>> I have tested iwctl and wpa_cli. The first one show only one ssid = the second one >>> all the access point. iw scan show all of them >>=20 >> The wpa_cli shows BSSIDs and so does iw. You see every single BSSID = broadcasting. iwd works on networks. Every BSSID with the same SSID and = matching security settings gets merged into a network. As it is meant to = be done by the WiFi spec. >>=20 >=20 > Ok, now it's clear. So iwd re-use the same password. Do you know if > wpa_supplicant does the same? I lost track of what wpa_supplicant does. We always found that whatever = it does it is half-baked. You have to think about it this way, the main = user is a human sitting in front of wpa_cli and typing commands. iwd is = meant to just work. You provide the passphrase (or other credentials) = and it does the job of keeping you connected. Regards Marcel