Manage Apache Download Speed And Traffic Limits With mod_cband

This article shows how to install and configure mod_cband on an Apache2 web server. mod_cband is an Apache2 module which provides bandwidth quota and throttling. It solves the problem of limiting users' and virtualhosts' bandwidth usage. The current versions can set virtualhosts' and users' bandwidth quotas, maximal download speed, requests-per-second speed and the maximal number of simultaneous IP connections.

http://www.howtoforge.com/mod_cband_apache2_bandwidth_quota_throttling