Re: Same Question
Sat, 22 Jul 1995 11:17:33 -0400

At 9:54 AM 7/22/95 -0248, Richard Collins wrote:
>What trick would be involved in sending something "out" from the
>reflector to initiate sending from a remote machine. I'm trying to make
>some remote systems around our province be a bit more Internet friendly.
>They'll be used for teaching sessions supplying video only from remote
>sites. Connectivity is the problem. If I could disconnect and connect
>to them only when the sessions are on the others using our frame-relay
>cloud would be much happier.
>They are set to auto-send. I just need to hit them with that initial
>packet (s) that will tell them the reflector wants a conversation with
>them. Is that a difficult thing.
>Surely anyone wishing to have cameras at remote site with
>"low-maintenance" would be interested in this idea!

To some extent, this feature is already built in. If you are connected to
a reflector but no one is receiving your video, then no video is sent. The
reflector "initiates" sending when it forwards a packet from another
participant that says they wish to receive your video. So, it sounds like
in your scenario you could simply leave the sending machine connected to
the reflector all of the time, and it would automatically provide video
whenever anyone was there to watch it.
This is not exactly what you describe because when no one else is
connected, the reflector and sender will still maintain a keep-alive
"conversation," exchanging a packet (of less than 100 bytes) every 3
seconds or so. This would seem to be a negligible load on your net, but
there is the problem that if network service is disrupted, the connection
would time out, and then it would have to be re-initiated from the desktop
machine. I can imagine other problems with maintaining a continual
connection (e.g., limiting machines use for other purposes), so there would
be value in what you suggest, and something like it will probably become
part of the protocol.
Tim Dorcey
Sr. Programmer/Analyst (607) 255-5715
Advanced Technologies & Planning
CIT Network Resources
Cornell University
Ithaca, NY 14850