[Testing] first play with new XO 1.5 machines

Daniel Drake dsd at laptop.org
Thu Oct 22 04:03:41 EDT 2009

2009/10/22 Martin Langhoff <martin.langhoff at gmail.com>:
> On Thu, Oct 22, 2009 at 4:03 AM, Daniel Drake <dsd at laptop.org> wrote:
>> We already discussed this a lot in another thread. It should not be
>> automatic. The thread is titled "[Sugar-devel] [Design] Ad-hoc
>> networks - New Icons"
> Yep -- I did read that thread, way back.
>> In ad-hoc, there is just one beacon master. Due to cheap radios and
>> interference etc, the beacon master will switch around frequently
> So there is a scheme for beacon master-y to switch around? If it works
> in practice -- that actually may do the right thing.

It rarely does. Ad-hoc is based on the concept "shout unless you hear
someone else shouting." In reality it just ends up with a lot of

>> 2. This kind of situation will happen frequently:
>> A <-----> B <-----> C
>> B can see both users A and C on his network view. A can only see B,
>> and C can only see B.
>> B shares an activity. Both A and C join. However, anything done by A
>> cannot be seen by C and vice-versa, because they are too far apart.
> Ok, but if they are close enough it will work. The question is: if we
> tell all our nodes to use the same ESSID (or a set of 3 ESSIDs, one
> per freq), will independently created networks join and split
> reasonably well?

No - ad-hoc is so simple that there is nothing in the design to make
this happen. It could happen by coincidence though, if circumstances
were to arise such that B were to become beacon master. This would
only happen if the existing beacon master dropped out for a while
*and* if B has a faster clock than the other remaining node.

But then, a few minutes later, consider B becoming the beacon master,
C hosting a shared activity with a new node D, which cannot see B.
Same problem, and no "coincidental" solution other than everyone
moving into good radio range of each another.

> If we wanted the unreliable mesh instead of the unreliable ad-hoc...
> On F11-XO-1.5 we are lacking
>  - 802.11s driver/firmware (which could be sub'd by open80211s)
>  - NM support (does it play ball w open80211s?)
>  - Sugar support.
> For F-11 on XO-1
>  - NM support
>  - Sugar support
> Would that be correct?

Yes. The XO-1 stuff is pretty much done - Sugar patches are available,
and the NM support is in NM-0.8 and scheduled to be included in NM-0.7
after the next release.


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