Ive got an internet cafe in which I have 30 clients ...Iam using a debian router and my network I just working fine..now it is obvious that I need some way to limit bandwidth usage on the clients....so I chose SQUID and the WEBMIN user interface to administrate it..I read a couple of tutorials and man pages..Ive successfully installed and used SQUID but it does not give me the results I wanted to achieve...however there are some points that are not clear to me..

1- Does SQUID limit upload ? Ive only seen that i can limit downloads in the delay pools !!
2- Does SQUID limit the traffic generated by webcams and voice conversations . I.e. Internet traffic not sent to port 80.
3- Does anyone have a good idea on how to just limit the maximum transfer to the internet to 64kbps up/down...without having to worry for what the computer is using the mentioned bandwidth

First of all, Squid is not a total bandwidth limiting stuff. it just a web proxy program that cache and does some basic content filtering. as you mentioned above, squid is able to limit the download speed depends on your rule. for example, you might want to limit the speed of any .exe file after it reached 3MB of download.

maybe what you need is traffic shaping. i ran a shorewall firewall system with traffic shaping. so far, it does great for me. visit shorewall.net. hope this helps!