Scan wifi card on linux when connected-

hong zhang henryzhang62 at yahoo.com
Wed May 30 15:44:54 EDT 2007


when driver scans, it will scan all channels as
default. Driver supports about 32 channels on a/b/g.
Default scan time on each channel is 100ms. It takes
at least 3 seconds to complete scan job. If client is
associated with AP, for example at channel 6. If scan
is allowed, driver will leave channel 6 when it scan
on other channels. Unless AP konws driver is canning
and AP buffers packets for more than 3 seconds.
Otherwise, packets will be lost.

So I think normal scan is not allowed when connected.

--- Dan Williams <dcbw at redhat.com> wrote:

> On Wed, 2007-05-30 at 10:31 -0700, hong zhang wrote:
> > Magda,
> > 
> > When client is already associated with AP, iwlist
> will
> > not do scan (normal scan). You can disaasociate
> with
> > the AP and run iwlist again. See any difference.
> To 
> > verify what I said. You can put printk() on
> > ieee80211_notify_scan_done(struct ieee80211vap
> *vap)
> > to prove scan is done when iwlist is executed.
> 
> Sounds like a driver bug; if you look in the source
> for the SIOCSIWSCAN
> handler, does it dis-allow a scan when connected?
> 
> Dan
> 
> > 
> > ----henry
> > --- magda chelly <sandra26899 at yahoo.fr> wrote:
> > 
> > > Hello,
> > > 
> > > I'm trying to scan a wifi card on debian
> > > distribution,
> > > (armel:nokia n800), but with iwlist scan, it
> doesn't
> > > show me all the networks, the connected one,
> does
> > > not
> > > appear and others are missing.
> > > Can someone help me please.
> > > 
> > > Thanks,
> > > Magda,
> > > 
> > > 
> > >      
> > >
> >
>
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