I'll address all three responses I've seen...

> Interesting situation... Are all the WAPs in a room on different channels?
> Seems like that'd spread the load out. Having everyone load a 6MB file
> simultaneously seems like quite a load. Could the slide show be separated
> out do separate files? Wireless is nice in its simplicity of
> "installation" (no searching for ethernet cables, etc.), but a wired
> system could handle more traffic assuming there's adequate upstream
> bandwidth above the router. Maybe a mix of the two (wired for everyone who
> has an ethernet connector on their computer, wireless for the rest)? Or,
> how about real low power WAPs, forming a cellular network. I don't think
> the WLAN cards in the laptops would back off their power, though, so even
> though the WAPs would not interfere with each other, the WLAN cards in the
> machines probably would. Lotsa fun!

I haven't really seen any portable PCs in quite awhile without LAN
ports.  Or WiFi, for that matter.  And, since (in the future, at least)
we will control the model of PC to be used, we can pretty well
guarantee the presence of a LAN port.

My initial investigation is suggesting that of the four WAPs, two have
the same channel and the other two are on two other channels.  That
is, there are two channel 1 WAPs, one channel 6 WAP, and one
channel 11 WAP.  I'm not ENTIRELY certain of how two WAPs on
the same channel in close proximity will behave, but my understanding
is that the best one can hope for is that they'll figure it out and each
one gets some portion of a time slot affair.  They can't both talk at
once, because they're on the same channel.  And if they can't both
talk at once, it seems to me that having two going on the same
channel in the same space is WORSE than having one, because of
the overhead associated with tracking whose turn it is to talk, and
routing traffic, and all the other crap that is associated with multiple
devices on one channel.

We do have the possibility of gigabit ethernet from these classrooms
back to the servers.  I think if we put 120 students on switches back
to gigabit, we'd be a far sight better than we are right now.

>From Danny:

> If they're just subscribed to a display he controls, ideally using a
> client which supports multicasting, that's not a huge deal.

Not sure how it works.  I'll investigate more soon.  It does support
the prof being able to directly control one PC, or look at what they
are doing, or force his display onto theirs.  Haven't got the full
details yet.

>From Alex:

> What about a bittorrent client with a user friendly wrapper around it?
> I'm not too familiar with 802.11 networking but I believe that
> devices can talk to each other directly without going through the AP.

I was going to thumbs down this idea, but now that I think about it,
it doesn't sound that bad as a test distribution method.  After all, the
test would then not be available until the prof enters the room, powers
up her PC, and makes the torrent available.  Yes, 802.11 client devices
can form "ad hoc", peer-to-peer networks, but that requires some
changes to the current network settings, which makes it unlikely to
work in such a situation.

Thanks, guys!

Mike H.

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