[OLPC Networking] An AP-like XO ?
Hilton Garcia Fernandes
hgfernan at lsi.usp.br
Fri Aug 3 17:42:15 EDT 2007
thanks for the enligthening, informative and thought provoking answer. for
instance, i failed to notice the Wireless Repeater pages.
now think of a school with not all class rooms filled with XO laptops.
in the general case, it will be necessary to have a more powerful device
to connect the XOs to the school network, and then to the Internet. that
kind of device will be in the class rooms or school corridors and will
provide the neighbor XOs with the desired connectivity.
that device usually will be a conventional 802.11g AP, since 802.11s cards
are not widely available now. due to 802.11 infrastructured mode, the AP
will create a NAT for its clients, and due to the hypothesis above, the
client of an AP will have no way to see directly the clients of other APs.
in the general case, the school will be an archipelago of AP-centered
islands. and that is not good for many of modern teaching techniques the
XO will offer.
so, the idea would be to use an AP-like device that joins the mesh and
lets all XOs talk with each other, without isolating them in islands.
if we use XOs for APs, the additional advantage will be that no wireline
structure will be necessary to connect each AP to the school network, as
they will connect to each other, due to mesh.
so, this kind of architecture requires only power outlets, that will be
already available, due to the illumination. and not network outlets, that
in general will be not available.
All the best,
On Thu, Aug 2, 2007, MBurns <maburns at gmail.com> said:
> On 8/2/07, Hilton Garcia Fernandes <hgfernan at lsi.usp.br> wrote:
>> i heard some talk about a server, but not much about the structure of an
>> AP-like XO, that probably could be called the MPP.
> It might be useful to clarify what use case you are trying to solve as I
> think you might be thinking of one that does not directly blend with an
> MPP. On the other hand, I may just be misunderstanding you.
> the pages i can read usually describe the MPP as a normal XO with some
>> packages installed, but it would be nice to elaborate on the architecture
>> of an AP-like XO.
> Realize that an MPP--that is, an XO acting as a Mesh Port--is still just an
> XO. The differences are purely configuration- and not hardware-related.
> for instance, it won't be a mobile device anymore, since
>> it would be pluged to a wall outlet.
> This is not necessarily so. Modern builds automatically act as a Mesh
> Portal. So as long as an XO is connected to an infrastructure AP or has an
> ethernet connected via USB dongle, it will provide a wireless portal to
> other XOs through the mesh .
> it could have more powerful antennas to say the least.
> This is a different use than an MPP. For instance, something like the
> Wireless Repeater  might be something more to your thought process. The
> Wireless Repeater is a dummy device that extends the range of the wireless
> network in a stationary place. It has a solar panel and larger antennas. The
> active antennae that Jim mentioned is also an option, where it (essentially)
> aligns it self on a pivot spot for best wireless connectivity sharing.
> Pretty neat stuff.
> The Repeater and the Active Antenna are not going to be available at FRS,
> that is, first ship of the XOs. They are shortly thereafter peripherals (as
> I understand it).
>  http://wiki.laptop.org/go/Establishing_a_Mesh_Portal
>  http://wiki.laptop.org/go/Wireless_repeater
> Michael Burns * Intern
> One Laptop Per Child
Hilton Garcia Fernandes
Nucleo de Tecnologias sem Fio (NTSF) -- Wireless Technologies Team
Lab de Sistemas Integraveis Tecnologico (LSI) -- Integrable Systems Lab
Escola Politecnica (Poli) -- Engineering School
Univ S Paulo (USP)
Tel: (5511)3091-5676 (work)
Av. Prof. Luciano Gualberto,158 trav.3 CEP 05508-900
S. Paulo -- SP -- Brazil
Pagina inicial: http://www.lsi.usp.br/~hgfernan
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