[Server-devel] Testing 200 XO's in two weeks time for Nepal's pilot

Bryan Berry bryan.berry at gmail.com
Wed Mar 5 03:07:12 EST 2008


Michailis, thanks for your quick reply

> small schools, the school server is all that you need. In the 
> meantime, APs with controllable WDS behavior are recommended. 

I am not an expert on access points. Can you suggest a particular model
that meets this criteria?

>The solution to that problem is to be able to turn off WDS. The stock
>Linksys firmware doesn't do it, however OpenWRT and its variants can do
>it. 

I am not familiar w/ OpenWRT and its variants. Similar to my previous
question, is their an off-the-shelf AP where WDS can be disabled w/out
having to load OpenWRT?

To Mesh or not to Mesh?
Using regular access points, is there actually a mesh network at all? It
sounds like we are back to using a regular 802.11 g network. Jabber just
emulates the features of a mesh over a regular network.

We were really excited about kids using the mesh to connect to the
Internet from their own homes to and each other via the mesh at great
distances. Is this dream currently not a reality? If it is not currently
a reality, when can we expect it to work?

Two Networks?
Should we use AP's for the school but then also use Active Antennas so
that kids can connect to the Internet from home via the mesh?


Michailis, thanks for taking your time to answer my questions. I really
appreciate your help.


Bryan
Kathmandu
http://www.olenepal.org

On Mon, 2008-03-03 at 08:38 -0500, Michail Bletsas wrote:
> 
> 
> server-devel-bounces at lists.laptop.org wrote on 03/03/2008 02:38:00 AM:
> 
> 
> > Questions: 
> > 
> > 
> > How many XO's can a single active antenna support? We only have two
> > active antennas at the moment. 
> The answer is always traffic depedent. Given the current status of the
> collaboration software on the XO and assuming that the school server's
> ejabberd works correctly (shutting off multicast traffic on the XOs),
> you should be able to put 30-40 laptops per "active antenna". 
> You should always keep in mind that in "dense" deployments
> (classrooms), mesh is sub-optimal compared to standard access points
> (assuming that every XO can talk to the AP). That is because, you have
> all the path discovery control traffic overhead in mesh mode that you
> don't have in infrastructure mode. 
> 
> 
> > 
> > Should we buy extra regular access points to back up our active
> > antennas? Again, would love to know if particular AP is preferred
> and
> > how many XO's one can support. I read in the devel list today that
> the
> > WRT54G is not preferred. 
> Yes, if you can afford them, APs will give you much better performance
> in schools. The issue with the stock firmware in the WRT54Gs is that
> it tries to establish WDS peer links with every other WDS capable node
> in the vicinity. So if you have a few of them in a school, you can end
> up with multiple WDS tunnels between them. Add to that the multicast
> traffic from the XOs and you end up with no spectrum at all, due to
> multicast/broadcast retransmissions. 
> The solution to that problem is to be able to turn off WDS. The stock
> Linksys firmware doesn't do it, however OpenWRT and its variants can
> do it. 
> So the answer to whether you should/can use WRT54Gx APs is "only if
> you can upgrade them to an OpenWRT variant". 
> 
> We are working on HostAP support for the active antennas, so that for
> small schools, the school server is all that you need. In the
> meantime, APs with controllable WDS behavior are recommended. 
> 
> 




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