Internet traffic analysis (common rules)

Hello everyone!

I’m trying to find a good working value to use when determining the expected traffic load based upon the potential number of users that can possibly connect to an Internet-access network.

The system I am designing is a one-way satellite broadcast network with a dial modem channel return path. I figure I have about 20 Mbps of bandwidth available in the satellite outroute.

It seems that the relevant question is “What level of traffic would (normally) be generated for an Internet-access network?” And what is the peak levels (BHT) for such a system? I need to know how many simultaneous users would be drawing from the bandwidth and, on average, what a reasonable amout of bandwidth would be required or desired for each simultaneous user in kbps.

If anyone has an idea of a good “rule of thumb” for such designs, please let me know!

Thanks much in advance to anyone who can help!