The more direct way to run FreeSWITCH is to run it as "root". Being root, the all-powerful user, the Overlord of the server, a program running as root has no limits whatsoever: No limits on how much memory it can allocate, which network port it can listen to and send from, how many files it can open, which priority and nice level it can escalate, which file and directories it can read and write.
While obviously very convenient for a casual test installation (no integration problems: FreeSWITCH simply owns the machine and all its resources), many users refrain from it.
To limit the reach and damage that a FreeSWITCH process can do after going awry because of a bug (or a malicious exploitation of a bug), you had better run FreeSWITCH as a user with the minimum possible privileges. A "system" kind of user is the most logical choice: No password, no way to login, no affiliation to groups but to "daemon".
This is how it is already implemented by ready...