The real situation is:
one internet link 512K/512K need to be shared with up to 10 PC’s. Now it work by old and repaired Cisco PIX 501. But, sometimes happen situation, when some users use internet and do something like downloadig media – another user can’t open webpage by acceptable time. I think it is typical situation.
So, can I setup zeroshell, when for examle, 5 users use intenet – each have per IP 100Kbit(=512/5), 2 users use internet – each have per IP 256Kbit(=512/2) and so on. I also used pfsense, good project, but I can’t setup it for this case.
Frankly I don’t think this can be done. You must have a way to verify how many users are active each time (by arp?) and which of them are downloading.
The only thing that could be of assistance is to setup in QoS for each user a reserved bandwidth and allow them to be able to reach the line maximum. In this way your users will have at least a minimum bandwidth and depending on the usage they may have some more.