Help Needed: VoIP Billing System

[Zahara]

Hello All   I am analysing a VoIP billing application.  I need some info about a few things.  I'd appreciate all the help and details that you could provide.    Here is what we need to do:   Our customers connect to our gateway/gatekeeper through IP or PSTN (calling cards through IVR system).  We have 2 RADIUS servers.  I still don't know which RADIUS server they're going to be though.  We have a web-enabled application that will be used to view billing reports and to register and manage customers etc.   Authentication: This is what I have understood about the process:   RADIUS server and our web-enabled application will be sharing a database (we want Oracle) containing all the customer related info.  The gatekeeper (cisco 7206 VXR) receives a call request.  It is configured to ask the RADIUS server to authenticate the user.  RADIUS server is configured to check our user table for authentication.  For authentic users, the next step is authorization.   Authorization: There can be 3 types of callers.  prepaid, postpaid and calling cards.  My questions are:   1. Is RADIUS server responsible to check the customer's billing status before authorizing the calls? To see if the user has enough balance to go ahead with this call (e.g. for prepaid customers).   2. Who is responsible for monitoring this call (during as well as after the call)?   3. Who is responsible to monitor bong charges (for calling cards) and other distance charges at each billing increment during the call?   4. Who is responsible for disconnecting the call, as soon as the available balance is consumed?   5. How is this disconnection and monitoring process works?   6. Who stores the CDR's? Where are they stored? Can they be stored directly to our Oracle DB?   7. When do the CDR's become available to our web-enable application for reporting and processing? After the call ends?   Looking forward to hear from you.   Thanks.   Zahara.