Are 2 Mbps sufficient?

[Simon Hobson]

Rudi Verago [vlain] wrote:

>In my infrastructure (2Mbps) I have two video stream at 512 kbps 
>(totally about
>1 Mbps). Other minor stream, audio, control and so on about 300 kbps. In the
>remaining bandwidth i have to send vnc stream for 4/5 client. Is it possible?
>I don't think so because vnc on peaks server and client get very slowly
>(impossible to use thanks to TCP). Configurations on client side about
>compression, jpeg quality and encoding offer poor improvment. Is it 
>correct this
>analysis? I have to change desktop sharing tool?

Changing tool will not necessarily help, and may make things worse. 
If you have a certain number of pixels to transfer in a given time, 
then it requires a certain bandwidth to do it. You have three options 
to improve things :

1) reduce the amount of data to be transferred: smaller screen, less 
bits/pixel, less frequent updates

2) increase the bandwidth

3) make more efficient use of the bandwidth: better compression, 
multicast instead of unicastx4

Anyone know if it's possible to multicast to several clients with VNC 
? If not, then changing tools to something that can multicast the 
stream (ie one packet to all clients, instead of one packet per 
client) will improve things (all else being equal of course).

Simon

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Simon Hobson MA MIEE, Technology Specialist
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