[lca2018-chat] Notes from the "Decentralise all the things" BoF

[James Cameron]

On Mon, Mar 05, 2018 at 05:48:06PM +1300, martin f. krafft wrote:
> [...]
> 1. Trust in mesh networks — The OLPC project, as inactive as it may
>    be, always had the goal to enable collaboration in meshes, i.e.
>    kids in a class room linking up with each other. When you're
>    sitting next to each other, then trust is kinda easy, but what is
>    trust anyway? It's basically just a function of all the previous
>    encounters, and ideally should be evaluated at every new
>    encounter.

Hey, thanks for the write-up!

My attendance at the BoF was accidental; misidentified as someone
else, hence the unusual discussion about OLPC.  The lunch was great
though.  I couldn't stay beyond this point, but happy to give a bit
more detail.

Mesh wireless collaboration was for either;

(a) infrastructureless scenario of two or more kids under a tree.  No
default route.  No ping to rest of world.

(b) one or more kids near an access point, with other kids meshed to
the internet through them.

In the original model XO-1, with the usb8388 chipset and the libertas
driver, using mesh became unreliable in small groups at around six
nodes.  It was thought to be air time depletion.  So it was dropped.

Eight years later, I found that some of the unreliability was due to
missing scan results, in turn a bug in the libertas driver;

95320774fae71d7b22b970ef4267fcc4d1ad23d8 ("libertas: fix scan result
loss if SSID IE len 0")

Alternative wireless configurations include ad-hoc or the usual
access point modes.

Moving to the application level ...

Collaboration between Sugar desktop activities can use Telepathy
Salut, with link-local XMPP.  No authentication or authorisation.

Our port to Python 3 is coming up and Telepathy doesn't yet live in
the Python 3 world.

I'm inclined to either (a) find something modern that will more
securely establish user-level trust between laptops, (b) drop the
Telepathy layer and use UDP broadcast packets with AES and some
application-specific trust establishment, or (c) port Telepathy.

Disclosure: OLPC continues to pay me for consulting work.

-- 
James Cameron
http://quozl.netrek.org/