Today's mesh testing.

[Chris Ball]

Hi,

Daf and I got the school server jabberd/shared roster working today.
We connected/registered 32 laptops to it with mesh TTL set to 1 for
broadcast, and they were all able to see and join a shared chat session
with each other.  The workload on the spectrum analyzer increased from
18% (no-one connected) to 26% (all connected).  The chat session is
consistent -- no-one is dropping out and new messages are seen by each
laptop, with a few seconds of lag.

With the mass chat session still running, we shared a 500KiB PDF.  First
we joined the shared Read session with one laptop, and the download took
16 seconds to complete.  We then joined two more laptops at once, the
first download took 26 seconds and the second finished at 30 seconds.
Five more at once: all finished around 1m00s.  Ten more at once:  the
first finished at 2m18s, the last finished at 2m40s.  There were no
failures downloading the PDF.  The sharing was unicast TCP, with mesh
TTL set to 1, which explains the slightly worse than linear increase in
download time for more laptops downloading at once.

This is much more anecdotal than the full test plan, but we thought the
testers currently in Peru would want to know what they can expect from
the school server setup ASAP.  We don't have more laptops upgraded and
ready to join the network yet, but we don't have any reason to believe
we've saturated the network -- with the PDFs downloaded and Chat still
running, the duty cycle on the spectrum analyzer is now at 28%.  (In
general, wireless networks seem to start degrading around 40%.)

- Chris and Daf.
-- 
Chris Ball   <cjb at laptop.org>