Using VNC for a One-to-Many solution... WAS Re: Multicasting

Albert Crosby acrosby "at"
Sat, 17 Oct 1998 16:53:02 +0000

There's been a bit of discussion recently about using VNC in a classroom
for broadcasting the instructor's video to the user stations. 

I have to agree with the original suggestion, that having an IP multicast
version of the client and server would be the ideal solution.
Unfortunately, I can't volunteer to take on the project, and it would be a
different direction from the original VNC design, so I doubt that it's
something that would be a high item on a feature wish-list for the
development team....

In experimenting with WINVNC and the Windows viewer, I've found that about
9 stations can view the instructor's station at a time in one of my labs.
The instructor's station is a 166 Mhz Pentium MMX running Win95 with 32M, and the clients
are a mix of 66 and 166 machines.  Add additional stations, and the
client's don't get updated frequently enough to be useful.  The network
topology, btw, is 16M Token Ring.  With a faster server, more clients seem
to be OK.

One minor feature that I'd like to see added for the client that would
help with this problem is a variable requesting a delayed refresh
interval.  As odd as that sounds, for one-to-many operations in a
classroom, refreshes every 2 seconds will usually be enough.  And that
would enable more clients to be connected to a single server.  I'd prefer
a client setting, so that it would still be possible to connect for a
control session with a normal refresh rate.  (I could also see this being
useful over slow connections for control...)

BTW- I may set up a Linux box just to test using it as a proxy host for



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