multicast in visual basic?

forkus2000 · Post by **forkus2000** » 2006-01-05 00:31

Hello to the guru's.
I develop a techer-student application that need alll the student view the teacher screen at the same time, if this possible?
Can somebody send me some code or information?
My email is forkus2000@yahoo.com

Regards to all

rmoller · Post by **rmoller** » 2006-01-05 16:29

I googled for multicast vnc and up came among others

http://www2.in.tum.de/~ziewer/multicastvnc/

I don't know how or if they handle lost packets.

Post by **Rudi De Vos** » 2006-01-05 16:59

The biggest isue with multicast

+Speed controle. With TCP, it's the cpu and bandwidth that controle the speed. Viewer ask next update.
Using multicast, you move from viewer ask to server push.
If you restrict the use to LAN, classroom model you can easy overcome
this problem by using one TCP viewer for rate controle and X mulicast connections.

+All package need to be total independed.
order is unimportant
missed packages have no influnce.

+package loss:
Handle package lost may be overkill. The lost package will in most cases
already be to old and overwritten be a next package.
You better add something that send a little part of the screen (64x64) with
each update, so after 2 or 3 minutes you have send the complete screen
This also has the advantage, that a new multicast connection will not require a full screen refresh.