Re: [B.A.T.M.A.N.] Fwd: Re: increasing BATADV_FRAG_MAX_FRAGMENTS

[Christof Schulze <christof.schulze@gmx.net>]

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Hi 

> > During an experiment it was found, that
> > BATADV_FRAG_MAX_FRAGMENTS=16 allows ~72 clients to be connected to
> > one single access point.

> > would you mind sharing some details regarding the experiments you
> > performed ?  The reason for this question is that there is no 72
> > client limit we know of (unless fragmentation was disabled).

> you are very likely looking in the wrong direction. The number of
> clients allowed to connect to an AP is configurable and 72 is
> already way beyond what I would consider useful in real life – if
> your clients are actually supposed to be able to communicate unicast
> traffic.

> Since you are probably using OpenWRT for your tests, look at the
> configuration parameter maxassoc:
> http://wiki.openwrt.org/doc/uci/wireless

> I don't know the default that OpenWRT uses if you don't set it
> explicitly.  But there is a default limit set somewhere (take a look
> at hostapd.conf) and you might have discovered that by pushing it to
> the limit. It might as well be the limitation of your WiFi driver /
> hardware, though.
Thank you for your response.

maybe it is indeed a little far-fetched to point at batman at first.
On the other hand - the investigation has to start somewhere.

From your feedback and from feedback on IRC I gathered the following
list of possible issues and things to look at:
* there might be an issue with not enough multicast-traffic being
  allowed - hypothesis: The client could associate with the AP but
  no IP was received. 
* the bandwidth of the air (airtime) might be saturated. 
* There might be a driver issue

If it is known that no more than 70 clients per device is sensible,
then we have to consider actually setting some limits and using
maxassoc.

Christof


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