User Directory, SIP, and Verto

SIP and Verto in FreeSWITCH both use the same User Directory machinery and concepts. FreeSWITCH's User Directory (or, in FreeSWITCH parlance, simply the "directory") is the central registry for all data related to users' authentication and authorization.
After a default installation, out of the box, you'll find that FreeSWITCH is already provided with 20 users, with a default password, each one of them belonging to one or more groups. FreeSWITCH is able to send calls to a specific user or to an entire group. Also, in User Directory you can set variables linked to the user, or to the group. Those variables are then used by FreeSWITCH both in managing incoming calls and when originating calls. We'll see how those variables can be used to select an outbound telephony provider (ITSP) gateway specific for a user or a users...