Question on 802.11r

[Nicolas Cavallari]

On 12/11/2013 10:19, Antonio Quartulli wrote:
> On Tue, Nov 12, 2013 at 08:54:55AM +0000, michael-dev wrote:
>> Hi,
>>
>> Am 12.11.2013 05:36, schrieb Ben Greear:
>>> Now, I have a somewhat related question:  Should the station
>>> re-acquire DHCP lease after successfully roaming? ...
>>> So, it would be nice to skip
>>> DHCP, but I'm not sure if that is how real-world networks
>>> are configured?
>>
>> even without 802.11r when devices are roaming within the same SSID, some 
>> don't refresh DHCP after changing the BSSID. I believe a recent version 
>> of MAC OS was doing so and maybe others, though I'm not sure which HW/SW 
>> exactly was used on client side. So that is why I built DHCP-Snooping / 
>> IP+ARP-Filter on my APs in a way that those stations don't loose network 
>> connectivity.

When devices roams, they expect that the layer2 environment is the same.
They are not required to refresh any DHCP lease or anything.

> I would like to inject a suggestion here: another "easier" approach could be
> to use a sort of middleware on the APs which would take care of handling these
> kind of events (i.e. roaming) with low packet loss and little connection
> outage.
> 
> What I refer to is called batman-adv[1] and it is a (wireless) mesh routing
> protocol implemented as an in-tree kernel module.

What's wrong about using a regular bridge in this situation ?  The standard was partly
designed for using bridges behind APs after all.