Return-path: Received: from mail2.candelatech.com ([208.74.158.173]:48820 "EHLO mail2.candelatech.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751335AbdINUr0 (ORCPT ); Thu, 14 Sep 2017 16:47:26 -0400 Subject: Re: ROAM/CONNECT event with PORT_AUTHORIZED To: Denis Kenzior , Johannes Berg , Arend van Spriel , Arend van Spriel , Jouni Malinen References: <1505378361.31630.2.camel@sipsolutions.net> <1505389462.31630.6.camel@sipsolutions.net> <1505416658.31630.15.camel@sipsolutions.net> <9219316a-5556-6acf-30de-e9aa65a05706@gmail.com> <6d0ad07b-ca89-19a1-d3c2-ad94915b942a@candelatech.com> <5436d106-0b4a-9158-58bf-ff84b231cd19@candelatech.com> <8a26a838-adde-08f1-5f64-c98e1d947675@candelatech.com> <756be45c-fd13-56a7-b8d4-129c4fd07dc8@gmail.com> Cc: Avraham Stern , linux-wireless From: Ben Greear Message-ID: (sfid-20170914_224729_682601_2055C189) Date: Thu, 14 Sep 2017 13:47:25 -0700 MIME-Version: 1.0 In-Reply-To: <756be45c-fd13-56a7-b8d4-129c4fd07dc8@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 09/14/2017 01:35 PM, Denis Kenzior wrote: > Hi Ben, > > On 09/14/2017 03:29 PM, Ben Greear wrote: >> On 09/14/2017 01:26 PM, Denis Kenzior wrote: >>> Hi Ben, >>>> >>>> How do you re-confirm them? There are definitely cases where SSID/Security is the same but each >>>> AP has its own DHCP server and roaming between them will require getting a new DHCP address (on >>>> the same (NAT'd) subnet and with same gateway, likely as not). >>>> >>> >>> Using DHCPREQUEST to verify obtained parameters, or the DHCPv6 equivalent Confirm message. This obviously requires some integration between the dhcp daemon and >>> the supplicant. >> >> Do you want to allow the just-now-roamed station to use its old IP address(es) while you are >> confirming? > > I think it is sane to assume that the IP address _should_ be the same. The 802.11 spec expects this even. This is to handle bizarre networks that don't do this > properly. Can you point me to the section in the spec about this? >> If not, how is this different from just re-doing DHCP like normal? >> > > You get to use your old IP address. So e.g. your VoIP call doesn't disappear if you decide to switch access points. > >> And if so, you will in some cases be allowing duplicate IP addresses on >> a network? >> > > Life is never perfect ;) If you are breaking networks while trying to optimize something, then I think you are going about it wrong. Seems like we would need some way for the DHCP server and/or AP to proactively notify the station that they can skip DHCP, and default to not skipping. I vaguely recall that FT had some way to verify you were roaming to the same dhcp-domain or not, but honestly, it has been a long time since I read through that... Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com