[AG-TECH] AG on wireless

John Shalf jshalf at lbl.gov
Thu Mar 21 22:56:04 CST 2002

Allison Clark wrote:
> Hello,
> Is anybody running their ag node on wireless? If so what type of
> connectivity are you using?

Hi Allison!

Our robot is pretty much AG-on-wireless (802.11b).  However,
has just about enough capacity to handle a single two-way
video stream + audio.  So we operate the vic/vat on the
with unicast and bridge it in to a given AG session using a
simple multicast-unicast bridge.

It don't think you'd want to support a full-fledged AG
session on wireless though.  It would hammer the network. 
Just to give you an idea of the bandwidth constraints (you
needn't worry about what a Megabit is... the only concern is
how much of it required for an AG)
	Our AG uses a 100Megabit network and it uses >50% of that
for big meetings (ie 50Megabits).
	The wireless network has a claimed bandwidth of 11Megabits
(about 1/10 that of the wired network we use).  However,
most experiments with wireless indicate you really have
more like 7Megabits available for you to use.  So as you can
imagine, wireless is a bit underpowered for the Access Grid
(50megabits over a 7megabit connection would not work out
too well).

The new 802.11a wireless network standard provides more
bandwidth but
	* not sure if its enough for the AG
	* testing so far by our local wireless guru's at LBLNet
indicate that the range on these new devices is very small
(on the order of a few yards).  They work over a wider range
than a few yards, but at a much slower rate than what is


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