Integrate Asterisk and Kamailio to provide Calls, IM and presence

. Set up and Configure Asterisk + A2Billing 2. SOAP Apis for Account management Check Balance Top Up Call back Call history 3. Setup Kamailio or openSips 4. Users are registered to Kamailio. INVITE requests are routed through the Asterisk server. 5. Asterisk RealTime user integration with Kamailio's subscriber table. 6. PUBLISH, SUBSCRIBE and MESSAGE requests are handled by Kamailio. The above installations and configurations has to be done in Cent OS server. You can find the required deployment architecture as attachment. Please message me know if you have any questions. You are welcome to suggest any other approaches to accomplish our requirements. Thanks.