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' group, or for letting all phones belonging to the same group to ring concurrently for an incoming call, for adding a special value to the Call Detail Record accounting log, of for choosing to which dialplan context a call must be sent to.
We'll also see how to add users and groups to the User Directory.
In SIP, we can send calls to gateways (gateways are SIP servers that belongs to ITSPs or to other in-house services), and then will be the gateway that will take care of call routing and termination (connecting the call to the national or international PSTN). We'll see how to set up a gateway in a way that automatically registers our FreeSWITCH machine to the remote server, and send it authorization credentials when originating outbound calls.

In this chapter we will cover the following topics:

• User Directory concepts
• Authentication, Authorization and Accounting (AAA) in FreeSWITCH
• Exploring and Using the Example User Directory
• Adding Users, by Modifying the User Directory and Dialplan
• SIP gateways, DID numbers, Dialplan Contexts and ITSPs