[IAEP] "Mesh" Dreams = OLSR

Mike Dawson mikeofmanchester at gmail.com
Fri Sep 3 16:06:56 EDT 2010

Hi Reuben,

It's AP(802.11N + OLSRD) ---- AP(802.11B/G) ----- XO - that's it as it is...

Actually considered putting up routers outside the school to try and
form a cloud that would then link back to the school / library.
Haven't yet considered putting that on the XOs - we would need to put
some logic on them like if I'm connected / or see the network school
function as normal if not then run OLSRd.  Then we could put routers
w/panels up lamp posts, trees, etc.

Would be nice to do - actually have had reports of quite large mesh
accomplishments being done relatively densely with OLSR because it
keeps it's own table of routes in the normal memory.  Unfortunately at
the moment we would lack the development manpower to actually put that
into practice.  In theory would just be putting a script of some kind
in the if-up section.



On 03/09/2010, Reuben K. Caron <reuben at laptop.org> wrote:
> 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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