[IAEP] "Mesh" Dreams = OLSR

Reuben K. Caron reuben at laptop.org
Fri Sep 3 14:36:40 EDT 2010


Mike,

Thank you for the information!

To be clear, from what I understand from our discussions in the past  
you're topology looks like

AP(802.11A + OLSRD) ----- AP (802.11B/G) ----- XO

You have several AP(802.11A + OLSRD) acting as your backbone and they  
drop down to standard AP (802.11B/G) for connection to the XOs.

Please let me know if this is correct.

Out of curiosity: have you considered extending your OLSR network to  
the AP (802.11B/G)'s and installing the OLRSd binary on your XOs so  
the OLSR network can be extended beyond the school?

Thanks,

Reuben

On Sep 2, 2010, at 6:36 PM, Mike Dawson wrote:

> Hi,
>
> Sorry for my late reply to this.  Actually we use OLSR in Afghanistan
> to do our school networking like so:
>
> 1. An OLSR router (running openwrt Freifunk ; see freifunk.net )
> connects to the other routers in the school - that forms the backbone
> on one network (e.g. channel 6)
>
> 2. A vanilla OpenWRT router actually connects to the XOs in the class.
> We reduce the transmit power on that and run it on a different
> channel (e.g. 1 or 11)
>
> The plus side is that you get a pure wireless system that does not
> need network cabling / does not have cables getting killed by the
> environment.  The down side is you use more routers.  I think
> financially the costs are pretty similar.  Also you can now use
> 802.11n to get good speeds on the backbone.
>
> Seems to scale pretty nicely - we have 500 XOs in most schools.  Note
> though by design we are not using the collaboration on the school
> server but rather just through the AP - teachers are not that enthused
> by the prospect of kids being able to chat with anyone anytime.
>
> This has practically made doing the deployment in the field a bit
> easier - though the firmware is not always perfect and not always
> working out of the box with all hardware options.
>
> Regards,
>
> -Mike
>
>
>
> On 25/08/2010, Martin Langhoff <martin.langhoff at gmail.com> wrote:
>> On Tue, Aug 24, 2010 at 11:13 AM, Reuben K. Caron  
>> <reuben at laptop.org> wrote:
>>> Where Mesh != 802.11s but rather an adhoc, self healing, self
>>> organizing routable network.
>>
>> Cerebro gave a great working demo of what you describe. Don't know  
>> how
>> they compare.
>>
>> I think it is perfectly feasible to achieve what you want...
>>
>> - to do it seamlessly and with polish will take a ton of work
>>
>> - very few users will actually benefit because the "under a tree"
>> scenario covers IMHO most of our interesting use cases.
>>
>> People do talk about having a mesh that covers their whole town, and
>> it's great dream but not achievable with our current constraints
>>
>> - town-wide meshes are made of stationary nodes
>>
>> - the "mesh" approaches we're discussing burn CPU / battery...
>>
>> - perennially power-starved users will focus on use, not on
>> maintaining the communal mesh up
>>
>>> Imagine a world where Sugar on a Stick machines can communicate on  
>>> the
>>> same network as an XO laptop
>>
>> We have that now with ad-hoc and infra. Limited but we have it.
>>
>>> A world where mesh capabilities are
>>> hardware agnostic allowing anyone to bring up a mesh network by
>>> booting a live cd.
>>
>> Mesh is pixie dust for most people. Your 'imagine' lines will make  
>> the
>> imagine things that cannot be made to work _in the way people
>> imagine_. Some meshy things can be made to work in a lab. Others just
>> involve tradeoffs no sane user would take on...
>>
>> We've had bazillion threads about this, because mesh stokes passion.
>> Problem is... even if you had the magical code right now working
>> seamlessly... the cost/benefit ratio isn't good.
>>
>> cheers,
>>
>>
>>
>> m
>> --
>>  martin.langhoff at gmail.com
>>  martin at laptop.org -- School Server Architect
>>  - ask interesting questions
>>  - don't get distracted with shiny stuff  - working code first
>>  - http://wiki.laptop.org/go/User:Martinlanghoff
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>>



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