We are going to implement a SBO system for VoIP providers which require integration with Asterisk, a2billing, openVPN. Server will be located in cloud based VPS server over centOS operating system.
End users will be connecting to the server by OpenVPN, voice calls should be passed through asterisk .Asterisk web billing gui for adding gateways.
Adding client , Prefix , dialing plan viewing active calls, billing cdr ,etc.
We need support of an expert to integrate these different systems. Please apply only if you are confident enough to accomplish the project goals properly.