yum (RHEL/CentOs/SL/etc) has an option which allows you to limit the download rate/amount of bandwidth used to download packages. Here’s how you do it:

Edit the /etc/yum.conf file and add the following line:

 
throttle=50k

The above entry will limit the download rate to 50 kilobytes per second (note, not kilobits) when you do any yum command such as yum install or yum groupinstall , etc.

For Ubuntu/Debian users that use apt, please see this post