Re: NM suboptimal with weak signal strength, easy fix

[Derek Atkins <warlord MIT EDU>]

Saikat Guha <saikat cs cornell edu> writes:

> On Fri, 2007-06-01 at 17:55 -0400, Dan Williams wrote:
>> The driver is telling userspace that it has lost association with the
>> access point.  Future versions of NM will try harder to reconnect before
>> timing out, but I'm not convinced that "pinning" is the best thing to do
>> from an interaction perspective.
>
> From the driver's perspective, it is the right thing to do to report
> lost associations.
>
> However, the driver doesn't know whether it'll reacquire association
> soon or not; the user, however, may very well know. I suppose the driver
> or NM could employ some heuristics (extended periods of low signal
> strength = expect intermittent disassociations), which may be a better
> approach than pinning if it does the right thing at the right time.
>
> As for NM trying harder to reconnect, what I'd see is that NM would
> re-associate, but then it would try to re-acquire the DHCP lease (even
> when it is the same network (AP mac even), and the old lease is still
> valid).
>
> So perhaps, the fix would be to skip DHCP reacquisition if the old lease
> is still valid and you associate to the same network (ssid? ap mac?). 

Personally I'd rather NM do nothing at all and let the AP reassociate
on its own.  Don't tear down the connection right away.  Don't throw
away the DHCP lease.  Just... wait.  IFF the connection does not come
back on its own after some period of time, THEN it can try to change
to a different SSID.  But honestly 802.11 hardware can roam quite well
and comes back on its own just fine.  NM is way too quick to throw
away valid connection information when it's faced with a somewhat
flakey network.

-derek
-- 
       Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
       Member, MIT Student Information Processing Board  (SIPB)
       URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
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