I am using Fedora 17 LXDE spin. Just a few minutes ago I typed this command in a terminal as root and it took some time to download and install all the Perl related packages. There were more than 1000 packages as I remember and the total size of the download was also nearly 300 MB.
In redhat-based distros, the yum tool has a distro-sync command which will synchronize packages to the current repositories. This command is useful for returning to a base state if base packages have been modified from an outside source.