Here are my scattered thoughts about the $100 Laptop, NetBSD, and mesh
networking.

I have not been able to pinpoint the goals of the $100 Laptop project's
"meshes".  Is it for connectivity in a classroom, throughout a town,
or cross-country?  Is it for web browsing, P2P messaging and/or phone?
IP radio broadcast?  I ask because I am convinced that it will be
unnecessary, and enormously difficult, to deliver the mesh networking
"ideal" by the $100 Laptop's "due date" in 2006.  The ideal, to my
mind, is peer-to-peer broadband IP transport on a metro-scale radio
relay network.  But that is probably not what the $100 Laptop project
has in mind, though.  I am interested to hear more specifics.

I've worked on a "mesh" network in Urbana, Illinois, for a few years now.
Our small group's achievements are rather modest, but we have built a
good foundation for mesh experimentation, both in open-source software
(NetBSD improvements, routing software), and in the town (~32 rooftop
wireless routers).  Our project has been funded, in part, by the Open
Society Institute (OSI), which is interested in meshes as communications
infrastructure for the developing world.

For the networking geeks, here is the path from my house to a neighbor's
a few blocks away; it might be illuminating to enter the street addresses
into Google Maps:

traceroute to n308.w.washington (10.0.10.172), 64 hops max, 40 byte packets
 1  n801.s.walnut (10.0.237.100)  10.298 ms  8.088 ms  5.390 ms
 2  n113.w.washington (10.0.237.108)  58.029 ms  103.887 ms  7.903 ms
 3  n308.w.washington (10.0.10.172)  88.963 ms  7.013 ms  7.576 ms

Incidentally, TCP does not like that path.  I am using it interactively,
now, and it feels a bit like I have ssh'd to the moon....  The bad
performance on that path is not difficult to explain, and improving the
performance is possible, but it takes "warm bodies."

I grant remote access to our testbed to trusted developers who
want to study and improve a real-world multihop ad hoc wireless
network.  For folks who want to experiment on their own, the
Urbana testbed is reproducible, indoors or out, with off-the-shelf
components.  Some instructions for outdoor "nodes" are on-line,
<http://cuwireless.net/nodeconstruction>.

Dave

-- 
David Young             OJC Technologies
dyoung@ojctech.com      Urbana, IL * (217) 278-3933